Courseiva

CCNA 200-301 v2 (200-301) — Questions 12761350

1389 questions total · 19pages · All types, answers revealed

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1276
MCQmedium

Which term in the CIA triad refers to ensuring systems and data remain accessible when needed?

A.Availability
B.Integrity
C.Accounting
D.Confidentiality
AnswerA

Availability in the CIA triad ensures that systems and data are accessible to authorized users when they need them, addressing uptime, redundancy, fault tolerance, and resilience against denial-of-service attacks. The prompt's phrase 'ensuring systems and data can be accessed when needed' is the textbook definition of availability, making it the correct choice among the four options.

Why this answer

The term is availability. In plain language, availability means that authorized users should be able to reach systems, services, and data when they actually need them. If a service is down, overwhelmed, or otherwise unreachable, availability has been affected. This is different from confidentiality, which focuses on preventing unauthorized disclosure, and integrity, which focuses on preventing unauthorized change.

This distinction matters because the CIA triad appears often in security foundations and exam questions. Availability is not about whether data is secret or whether it has been altered; it is about whether the service is usable. That is why availability is the best answer here.

Exam trap

A frequent exam trap is confusing availability with confidentiality or integrity because all three belong to the CIA triad. Candidates may incorrectly choose confidentiality, thinking about data protection, or integrity, focusing on data accuracy. However, availability specifically means ensuring systems and data remain accessible when needed.

Misreading the question or overthinking the triad components leads to selecting the wrong term. Remember, availability is about uptime and access, not secrecy or correctness, which are confidentiality and integrity respectively.

Why the other options are wrong

B

Integrity is incorrect because it focuses on protecting data from unauthorized changes, not on ensuring access or uptime of systems and data.

C

Accounting is incorrect as it is part of the AAA framework (Authentication, Authorization, Accounting) and not a component of the CIA triad, so it does not relate to system availability.

D

Confidentiality is incorrect because it deals with preventing unauthorized disclosure of information, not with ensuring that systems and data are accessible when required.

When would these options actually be correct?

B

In a question asking about the importance of maintaining data accuracy during a data transfer process, where the focus is on preventing unauthorized changes to the data, 'Integrity' would be the correct answer. For example, 'Which term ensures that data remains unaltered during transmission?'

C

If the exam question asked about the importance of tracking user access and resource utilization for compliance or auditing purposes, then 'Accounting' would be the correct answer, as it pertains to maintaining records of system usage.

D

In a question asking about measures to protect sensitive information from unauthorized disclosure, such as encryption methods or access controls, 'Confidentiality' would be the correct answer. For example, a question might ask, 'What principle ensures that only authorized users can access sensitive data?'

Why candidates pick the wrong answer

B

Candidates may confuse integrity with availability due to their interconnectedness in security discussions, leading them to mistakenly believe that ensuring data accuracy also implies accessibility.

C

Candidates may confuse 'Accounting' with the broader concept of system management and oversight, leading them to mistakenly believe it relates to ensuring system availability.

D

Candidates may confuse confidentiality with availability due to their interconnectedness in security practices, leading them to mistakenly believe that protecting data access also implies ensuring it is available.

1277
Multi-Selectmedium

Which TWO statements correctly describe the configuration and use of a voice VLAN on a Cisco switch port?

Select 2 answers
A.The voice VLAN is configured using the 'switchport mode trunk' command.
B.When a voice VLAN is configured, the switch port operates in two VLANs: one for data and one for voice traffic.
C.The voice VLAN must be the same as the native VLAN on the trunk link.
D.The IP phone uses CDP or LLDP to learn the voice VLAN ID from the switch.
E.The data VLAN and voice VLAN must be in the same IP subnet.
AnswersB, D

With a voice VLAN configured, a single physical switchport simultaneously carries data and voice traffic by operating as an access port for the data VLAN and accepting tagged frames on the voice VLAN. The switch sets the port to 'switchport mode access' with 'switchport access vlan' for data and 'switchport voice vlan' for voice, so the port effectively bridges two separate VLANs. This is why a PC connected through an IP phone still gets an untagged data VLAN assignment while the phone's traffic is tagged with the voice VLAN ID.

Why this answer

When a voice VLAN is configured on a Cisco switch port, the port operates in two separate VLANs simultaneously: one for data traffic (the access VLAN) and one for voice traffic (the voice VLAN). This is achieved using the 'switchport voice vlan' command, which allows the switch to tag voice frames with the voice VLAN ID while leaving data frames untagged (or tagged with the access VLAN). This separation ensures that voice traffic receives appropriate QoS treatment and is isolated from data traffic.

Exam trap

Cisco often tests the misconception that a voice VLAN requires trunking or that the voice VLAN must match the native VLAN, but in reality, a voice VLAN is configured on an access port using the 'switchport voice vlan' command, and the native VLAN concept applies only to trunk ports.

Why the other options are wrong

A

Trunk mode is used to carry multiple VLANs, but for a single access port with voice, the port remains in access mode and uses the voice VLAN feature.

C

The native VLAN is used for untagged traffic on a trunk, while the voice VLAN is a specific VLAN that carries tagged voice traffic from the phone.

E

They are separate VLANs and usually belong to different subnets for logical separation and management.

1278
PBQeasy

You are connected to SW1, a Layer 2 switch. The network administrator wants to prevent unauthorized switches from being connected to access ports. Port G0/1 is an access port in VLAN 10. You need to configure BPDU Guard on this port to protect against STP loops caused by rogue switches. Additionally, enable PortFast for immediate transition to forwarding.

Hints

  • PortFast should be applied to access ports to reduce STP convergence time.
  • BPDU Guard disables the port if a BPDU is received.
  • Both commands are under the interface configuration.
A.SW1(config-if)# spanning-tree portfast SW1(config-if)# spanning-tree bpduguard enable
B.SW1(config)# spanning-tree portfast default SW1(config)# spanning-tree bpduguard default
C.SW1(config-if)# spanning-tree portfast SW1(config-if)# spanning-tree guard root
D.SW1(config-if)# spanning-tree portfast SW1(config-if)# spanning-tree bpduguard disable
AnswerA
solution
! SW1
interface GigabitEthernet0/1
spanning-tree portfast
spanning-tree bpduguard enable

Why this answer

PortFast allows an access port to skip STP listening/learning and transition immediately to forwarding. BPDU Guard protects against STP loops by error-disabling the port if a BPDU is received, which would indicate an unauthorized switch connection.

Exam trap

Be careful to distinguish between interface-level and global commands for PortFast and BPDU Guard. Also, remember that BPDU Guard uses 'bpduguard enable' (not 'disable') and is different from Root Guard ('guard root').

Why the other options are wrong

B

The specific factual error is that global commands affect all ports, not a single interface.

C

The specific factual error is confusing Root Guard with BPDU Guard; they serve different purposes.

D

The specific factual error is using the 'disable' keyword instead of 'enable' to activate BPDU Guard.

Why candidates pick the wrong answer

B

Candidates pick this because they know PortFast and BPDU Guard can be enabled globally, but they overlook the requirement to configure only one specific port.

C

Candidates pick this because both features protect the STP topology, but they confuse the commands and their functions.

D

Candidates pick this because they might think 'disable' is the correct syntax to enable the feature, or they misremember the command.

1279
MCQeasy

Which STP port state on a classic 802.1D switch listens for BPDUs and prepares to participate in the topology, but does not yet learn MAC addresses?

A.Listening
B.Learning
C.Forwarding
D.Disabled
AnswerA

In the classic 802.1D listening state, a port is still blocked from forwarding user data, but it is actively listening to incoming BPDUs to determine the network topology. During this 15-second forward-delay interval, the switch does not learn MAC addresses from the frames it receives, and it cannot send user traffic. Only after this state does the port move to learning.

Why this answer

In classic STP, the listening state processes BPDUs and waits before learning begins. The learning state is when the switch starts populating the MAC table.

Exam trap

Do not confuse the listening state with the learning state; remember that listening involves BPDU processing without MAC address learning.

Why the other options are wrong

B

In the listening state, a switch port listens for BPDUs but does not learn MAC addresses. The learning state is the next step where the port begins to learn MAC addresses from incoming frames while still not forwarding traffic.

C

In the Forwarding state, the switch port has already learned MAC addresses and is forwarding data frames, whereas the question specifies a state that does not yet learn MAC addresses.

D

The Disabled port state does not listen for BPDUs, learn MAC addresses, or forward frames; it is administratively shut down and has no participation in STP topology.

When would these options actually be correct?

B

This option would be correct for a question asking: 'Which STP port state on a classic 802.1D switch learns MAC addresses but does not yet forward data frames?'

C

This option would be correct for a question asking: 'Which STP port state on a classic 802.1D switch forwards data frames and learns MAC addresses?'

D

This option would be correct in a question asking: 'Which STP port state indicates that the port is administratively down and does not participate in spanning tree?'

Why candidates pick the wrong answer

B

Candidates often confuse the order of STP states (blocking, listening, learning, forwarding) and mistakenly think that learning includes both BPDU listening and MAC learning, or they misremember the specific function of each state.

C

Candidates may confuse the sequence of STP states, thinking that Forwarding is the first active state, or they may misremember that learning MAC addresses occurs only in the Forwarding state.

D

Candidates may confuse 'Disabled' with a state that is inactive but still listening, or they might think a disabled port can still receive BPDUs, which is incorrect.

1280
PBQhard

You are connected to R1, a Cisco IOS-XE router. Configure SNMP v2c with read-only community 'NetOpsRO' and SNMP v3 with user 'AdminUser' using SHA authentication (password: AuthPass1) and AES-128 encryption (password: PrivPass2). Also enable SNMP traps to the NMS at 192.0.2.10 with community 'TrapComm'. Additionally, configure NetFlow export to 192.0.2.20 using version 9, and ensure the flow exporter is applied to GigabitEthernet0/0. Verify your configuration using 'show snmp' and 'show ip cache flow'.

Network Topology
G0/010.0.0.1/30G0/010.0.0.2/30linkR1R2

Hints

  • SNMPv3 requires both a group and a user; the group defines the security level (auth/priv).
  • NetFlow export requires a flow exporter and a flow monitor applied to the interface.
  • Use 'snmp-server enable traps' without specific traps to enable all supported traps.
A.snmp-server community NetOpsRO ro snmp-server group AdminGroup v3 priv snmp-server user AdminUser AdminGroup v3 auth sha AuthPass1 priv aes 128 PrivPass2 snmp-server enable traps snmp-server host 192.0.2.10 TrapComm flow exporter EXPORTER destination 192.0.2.20 version 9 ! flow monitor FLOW-MONITOR exporter EXPORTER record netflow ipv4 original-input ! interface GigabitEthernet0/0 ip flow monitor FLOW-MONITOR input
B.snmp-server community NetOpsRO ro snmp-server user AdminUser v3 auth sha AuthPass1 priv aes 128 PrivPass2 snmp-server enable traps snmp-server host 192.0.2.10 TrapComm flow exporter EXPORTER destination 192.0.2.20 version 9 ! interface GigabitEthernet0/0 ip flow export EXPORTER
C.snmp-server community NetOpsRO ro snmp-server group AdminGroup v3 priv snmp-server user AdminUser AdminGroup v3 auth sha AuthPass1 priv aes 128 PrivPass2 snmp-server enable traps snmp-server host 192.0.2.10 version 2c TrapComm flow exporter EXPORTER destination 192.0.2.20 version 9 ! interface GigabitEthernet0/0 ip flow monitor FLOW-MONITOR input
D.snmp-server community NetOpsRO ro snmp-server group AdminGroup v3 priv snmp-server user AdminUser AdminGroup v3 auth sha AuthPass1 priv aes 128 PrivPass2 snmp-server enable traps snmp-server host 192.0.2.10 TrapComm flow exporter EXPORTER destination 192.0.2.20 version 9 ! interface GigabitEthernet0/0 ip flow monitor FLOW-MONITOR input flow monitor FLOW-MONITOR exporter EXPORTER
AnswerA
solution
! R1
snmp-server group AdminGroup v3 priv
snmp-server user AdminUser AdminGroup v3 auth sha AuthPass1 priv aes 128 PrivPass2
snmp-server enable traps
flow exporter EXPORTER
 destination 192.0.2.20
 transport udp 9996
 template data timeout 60
 exit
flow monitor FLOW-MONITOR
 exporter EXPORTER
 record netflow ipv4 original-input
 exit
interface GigabitEthernet0/0
 ip flow monitor FLOW-MONITOR input
 exit

Why this answer

The only complete configuration. It defines the SNMPv3 group and user, enables traps, sets up the flow exporter, and crucially defines a flow monitor globally before applying it to the interface. Without the global `flow monitor` definition, the `ip flow monitor ... input` command on the interface would be rejected.

Option B omits the SNMP group and uses the deprecated `ip flow export` instead of the modern flow monitor method. Option C is missing the flow monitor definition, and its `snmp-server host` version syntax is unnecessary but not harmful; the real flaw is the absent monitor. Option D attempts to add the flow monitor but incorrectly places the global definition commands inside the interface configuration, which would cause a syntax error.

Exam trap

The most common oversight is forgetting to define the flow monitor globally; without it, the `ip flow monitor` command on the interface will fail. Also, learners sometimes mistakenly use the deprecated `ip flow export` command instead of the modern flow monitor approach.

Why the other options are wrong

B

Missing the required SNMPv3 group and relies on the deprecated interface command 'ip flow export' instead of the modern flow monitor method.

C

Lacks the required global flow monitor definition block; the 'ip flow monitor' command on the interface refers to a nonexistent monitor.

D

Places the flow monitor definition commands inside the interface configuration context, where they would be rejected as invalid.

Why candidates pick the wrong answer

B

Candidates might think that the SNMPv3 user can be created without a group if the group is implied, and they may confuse 'ip flow export' with the correct 'ip flow monitor' command.

C

Candidates might assume that applying a flow monitor to an interface automatically uses a preconfigured exporter, but the flow monitor must explicitly reference the exporter.

D

Candidates might think that the flow monitor can be configured in any order, but Cisco IOS requires the flow monitor to exist before it can be applied to an interface.

1281
MCQhard

A network technician configures a Windows 10 PC with a static IPv6 address of 2001:db8:acad:1::100/64 and a default gateway of 2001:db8:acad:2::1. The PC can communicate with other hosts in the 2001:db8:acad:1::/64 subnet, but it cannot access any resources on other subnets, even though IPv4 connectivity through the same network works normally. What is the most likely reason for this issue?

A.The PC's default gateway address is in a different subnet than the PC's IPv6 address.
B.The PC's IPv6 stack has a corrupted binding that prevents routing.
C.The router's IPv6 routing table does not have a route back to the PC's subnet.
D.The DNS server for IPv6 resolution is misconfigured, causing all off-subnet traffic to fail.
AnswerA

An IPv6 host only uses a default gateway if it is on the same subnet. Since 2001:db8:acad:2::1 is in a different /64 subnet than the PC's 2001:db8:acad:1::100/64, the host considers the gateway unreachable and cannot send traffic beyond the local link.

Why this answer

The PC's IPv6 address is 2001:db8:acad:1::100/64, placing it in the 2001:db8:acad:1::/64 subnet. The configured default gateway is 2001:db8:acad:2::1, which belongs to the 2001:db8:acad:2::/64 subnet. For IPv6, a host will only consider a default gateway on the same link-local or on-link subnet; if the gateway address is not within the same /64 prefix as the host's address, the host cannot send packets to it directly, and all off-subnet traffic fails.

Exam trap

Cisco often tests the concept that an IPv6 host will only use a default gateway that is within the same subnet (same /64 prefix) as its own configured IPv6 address, unlike IPv4 where a gateway in a different subnet can still be used if the host has a route to it.

Why the other options are wrong

B

This is a less common and less specific cause; the symptom points directly to a misconfigured gateway address in a different subnet.

C

This option assumes a routing problem on the router, but the scenario indicates the PC cannot send packets to its gateway, which points to host configuration, not routing tables.

D

DNS misconfiguration would cause failures when using hostnames, but not for direct IP connectivity tests like pinging a remote IPv6 address.

1282
MCQhard

A host is configured as 10.10.20.190/26. Which range contains usable host addresses for that subnet?

A.10.10.20.129 to 10.10.20.190
B.10.10.20.128 to 10.10.20.191
C.10.10.20.130 to 10.10.20.191
D.10.10.20.193 to 10.10.20.254
AnswerA

A /26 prefix length yields a 64-address block. Since the address 10.10.20.128 falls on a 64-byte boundary, the subnet's network address is 10.10.20.128 and its broadcast address is 10.10.20.191. Therefore, the usable host addresses are exactly 10.10.20.129 through 10.10.20.190, as this excludes the network and broadcast identifiers while including every valid host in that range.

Why this answer

A /26 uses blocks of 64 addresses. In plain language, the ranges are 0–63, 64–127, 128–191, and 192–255. Since the host ends in 190, it belongs to the 128–191 block. In that block, 10.10.20.128 is the network address and 10.10.20.191 is the broadcast address. That leaves 10.10.20.129 through 10.10.20.190 as the usable host range.

This question checks whether you can identify the correct block and then exclude the reserved endpoints properly.

Exam trap

Be careful not to include the network and broadcast addresses as usable host addresses. Always calculate the subnet boundaries accurately.

Why the other options are wrong

B

Option B is incorrect because it includes the network address (10.10.20.128) and the broadcast address (10.10.20.191) for the subnet 10.10.20.128/26, which are not usable host addresses.

C

Option C is incorrect because the subnet mask /26 indicates a subnet range of 10.10.20.128 to 10.10.20.191, but the usable host addresses are from 10.10.20.129 to 10.10.20.190, excluding the network and broadcast addresses.

D

Option D is incorrect because the range 10.10.20.193 to 10.10.20.254 falls outside the subnet defined by 10.10.20.190/26, which only allows for usable addresses from 10.10.20.130 to 10.10.20.190.

When would these options actually be correct?

B

If the question asked for the range of addresses in the subnet 10.10.20.128/26, then option B would be correct, as it would include all usable addresses from 10.10.20.129 to 10.10.20.190, while still including the network and broadcast addresses.

C

If the question specified a subnet mask of /25 instead of /26, then option C would be correct, as the usable host range would then be 10.10.20.129 to 10.10.20.254, allowing for addresses up to 10.10.20.191.

D

If the question specified a different subnet, such as 10.10.20.192/26, then option D would be correct, as it would contain usable addresses from 10.10.20.193 to 10.10.20.254 for that subnet.

Why candidates pick the wrong answer

B

Candidates may choose this option because it appears to include a broader range of addresses, and they might mistakenly believe it encompasses usable addresses without recognizing the significance of the network and broadcast addresses.

C

Candidates may choose this option due to a misunderstanding of subnetting, confusing the usable range with the total range of addresses, or miscalculating the subnet boundaries.

D

Candidates may be tempted by option D because it includes addresses that are numerically close to the given host address, leading to confusion about the correct subnet range.

1283
MCQhard

A technician is troubleshooting a connection between two routers, R1 and R2, connected back-to-back using Ethernet cables. Both routers have their interfaces configured and are in an 'up/up' state. R1's interface uses 192.168.1.1/24, and R2's interface uses 192.168.2.1/24. When the technician attempts to ping R2 from R1, the ping fails. What is the most likely cause?

A.The Ethernet cable is faulty, causing intermittent physical layer failures.
B.A duplex mismatch exists between R1 and R2, causing one-way communication.
C.A routing protocol is not configured to allow the routers to learn about each other's directly connected networks.
D.The IP addresses assigned to the interfaces belong to different subnets, preventing direct Layer 3 communication.
AnswerD

When two devices are in the same broadcast domain and have IP addresses in different subnets, they do not consider each other as local destinations. Router R1 will not attempt to ARP for 192.168.2.1 because it believes that address is in a different network, making the ping fail even though link status is up/up.

Why this answer

The ping fails because R1's interface is configured with IP address 192.168.1.1/24, which places it in the 192.168.1.0/24 subnet, while R2's interface uses 192.168.2.1/24, placing it in the 192.168.2.0/24 subnet. For two devices to communicate directly at Layer 3 over a single Ethernet link, their IP addresses must belong to the same subnet. Since these addresses are in different subnets, R1 will see the destination as unreachable and will not even attempt to send an ARP request for R2's MAC address, resulting in a failed ping.

Exam trap

Cisco often tests the concept that directly connected devices must share the same subnet, and the trap here is that candidates assume 'up/up' means Layer 3 connectivity is guaranteed, or they mistakenly think a routing protocol is needed to exchange routes between directly connected interfaces.

Why the other options are wrong

A

Candidates might suspect a physical issue first, but the up/up status definitively rules out a cable or hardware problem.

B

Candidates commonly associate ‘cannot ping’ with duplex mismatches, forgetting that the fundamental issue here is the IP subnet mismatch.

C

The trap is thinking that a routing protocol is always needed for inter-subnet communication, overlooking that directly connected devices on the same broadcast domain must share a common subnet.

1284
Multi-Selectmedium

Which TWO commands would a network engineer use to verify that a Windows client has received an IP address from a DHCP server and can resolve a domain name to an IP address?

Select 2 answers
A.ping 8.8.8.8
B.ipconfig /all
C.tracert www.courseiva.com
D.nslookup www.courseiva.com
E.arp -a
AnswersB, D

ipconfig /all is the correct command because it displays the full TCP/IP configuration for every network adapter on the system. It explicitly shows whether DHCP is enabled, the DHCP server address, the lease obtained and lease expiration times, and the IP address currently assigned by DHCP, which directly confirms that the DHCP process has completed successfully. It also lists the configured DNS servers and other vital Layer 3 details, making it the definitive tool for diagnosing IP addressing issues in a DHCP environment.

Why this answer

`ipconfig /all` displays the full TCP/IP configuration for all adapters, including whether the IP address was obtained from a DHCP server (the DHCP Enabled and DHCP Server fields). Option D is correct because `nslookup www.courseiva.com` queries the configured DNS server to resolve the domain name to an IP address, confirming DNS resolution works.

Exam trap

Cisco often tests the distinction between connectivity verification (ping) and configuration verification (ipconfig /all, nslookup), leading candidates to mistakenly select ping or tracert as tools for confirming DHCP and DNS functionality.

Why the other options are wrong

A

It checks network reachability, not DHCP or DNS.

C

It shows the path taken, not DHCP or DNS status.

E

It shows Layer 2 address mappings, not DHCP or DNS.

1285
MCQmedium

R1 receives an OSPF route to 10.55.0.0/16 and already has a static route to 10.55.10.0/24. Which route will be used for traffic sent to 10.55.10.25?

A.The OSPF /16 route, because dynamic routes override static routes learned later.
B.The static /24 route, because it is the longest-prefix match.
C.Both routes equally, because they point to the same major network.
D.Neither route, because overlapping routes are invalid.
AnswerB

The router performs a longest-prefix-match lookup in its forwarding table, and 10.55.0.0/24 has a longer prefix (more specific) than 10.55.0.0/16. Because the static route matches more bits of the destination address, it is the best route for any traffic destined to that subnet. This rule takes precedence over administrative distance or route source, so the /24 static route is always selected over the /16 OSPF route.

Why this answer

The static /24 route is more specific than the OSPF /16 route, so longest-prefix match wins. Administrative distance is only compared among routes to the same prefix length.

Exam trap

Remember that the longest-prefix match rule takes precedence over administrative distance when routes have different prefix lengths.

Why the other options are wrong

A

This option is incorrect because static routes are preferred over dynamic routes in OSPF when both are present, regardless of when they were learned. The static route to 10.55.10.0/24 will be used due to its longer prefix match.

C

This option is incorrect because OSPF routes do not share equal preference with static routes; the static /24 route will be preferred due to its longer prefix length, making it the best match for the specific destination IP.

D

This option is incorrect because overlapping routes are valid in routing protocols like OSPF, and both routes can coexist in the routing table. The static route to 10.55.10.0/24 is valid and will be preferred due to its longer prefix length.

When would these options actually be correct?

A

In a scenario where the question states that OSPF routes are configured with a higher administrative distance than static routes, the OSPF /16 route could override the static route. For example, if the static route had an administrative distance of 200 and the OSPF route had an administrative distance of 110, the OSPF route would be used.

C

In a different scenario where both routes are configured with equal administrative distances and no specific prefix matching rules apply, a question might ask which route would be used if both were equally preferred. In such a case, the answer could be that both routes are considered equally valid for traffic to the same major network.

D

In a different scenario, if the question stated that the routing table had a configuration that explicitly marked overlapping routes as invalid or if the router was configured to reject any overlapping static routes, then this option could be correct.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of OSPF's behavior, believing that dynamic routes always take precedence over static routes, especially if they are not familiar with the concept of administrative distance.

C

Candidates may find this option tempting because it suggests that multiple routes can be utilized simultaneously, reflecting a common networking concept where multiple paths exist for the same destination.

D

Candidates may choose this option due to a misunderstanding of how routing protocols handle overlapping routes, mistakenly believing that any overlap renders routes invalid rather than recognizing the preference rules that apply.

1286
MCQhard

A switch interface is configured as `dynamic desirable`, and the peer interface is configured as `dynamic auto`. What is the most likely result?

A.The link is likely to become a trunk.
B.The link becomes a routed port.
C.All VLANs are deleted from both switches.
D.The port is immediately error-disabled.
AnswerA

Dynamic desirable is the most proactive DTP mode; it actively sends DTP frames to initiate trunk negotiation. When the remote switch port is configured as dynamic auto, it passively listens and responds to DTP, allowing the two switches to agree on trunking and place the link into trunk mode. Therefore, this pairing is a valid and expected way to form a trunk.

Why this answer

The most likely result is that the link becomes a trunk. In simple terms, `dynamic desirable` actively tries to negotiate a trunk, while `dynamic auto` listens and responds. Because one side is willing to initiate the process, trunking can be established if the rest of the configuration is compatible.

This question tests whether you know the difference between passive and active DTP behavior. The classic failure pairing is auto/auto. Desirable/auto, by contrast, is a normal path to trunk formation.

Exam trap

Be careful not to confuse DTP modes with Spanning Tree Protocol states or assume passive modes prevent trunking.

Why the other options are wrong

B

This option is wrong because a switch interface configured as `dynamic desirable` and its peer as `dynamic auto` will negotiate a trunk link, not a routed port. Routed ports are typically configured explicitly and not through dynamic negotiation.

C

This option is wrong because configuring a switch interface as `dynamic desirable` and `dynamic auto` does not lead to the deletion of VLANs; it instead allows for trunk negotiation between the switches.

D

This option is wrong because a switch interface configured as `dynamic desirable` and its peer as `dynamic auto` will negotiate a trunk link, not a routed port. Routed ports are typically configured explicitly and do not involve dynamic negotiation.

When would these options actually be correct?

B

In a different scenario where a switch interface is configured as a routed port and the peer interface is also set to routed, the link would indeed become a routed port. The question would need to specify that both interfaces are configured for routing rather than dynamic negotiation.

C

In a different scenario, if the question specified that both switches were configured to use `vlan access` mode and that a VLAN pruning command was executed, it could lead to the deletion of VLANs from the trunk, making this option correct.

D

In a different scenario, if the question specified that both interfaces were configured for Layer 3 routing and that the switch was set to operate in a routed mode, then the link could be described as a routed port. This would involve a configuration where Layer 2 switching is not intended.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of how dynamic negotiation works, conflating it with routed port configurations, which can lead to confusion about the roles of switch interfaces.

C

Candidates might choose this option due to a misunderstanding of VLAN management and trunking, confusing the negotiation process with VLAN deletion when misconfigurations occur.

D

Candidates may choose this option due to a misunderstanding of port roles and the assumption that dynamic configurations could lead to a routed state, especially if they confuse Layer 2 and Layer 3 concepts.

1287
Matchingmedium

Drag and drop the cable/transceiver types on the left to the correct distance and speed descriptions on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

100 m at 1 Gbps

300 m at 10 Gbps

5 km at 1 Gbps

55 m at 10 Gbps

10 km at 10 Gbps

Why these pairings

Option A is correct: Cat5e UTP supports 1000BASE-T at 100 m and 1 Gbps. Option B is incorrect: Cat6 supports 10GBASE-T only up to 55 m; it requires Cat6A for 100 m at 10 Gbps. Option C is correct: 1000BASE-LX over single-mode fiber has a standard reach of 5 km at 1 Gbps.

Option D is correct: 1000BASE-SX over 50 µm multimode fiber has a standard reach of 550 m at 1 Gbps.

Exam trap

Be careful not to assume that Cat6 supports 10 Gbps at 100 meters; IEEE specifies 55 meters for 10GBASE-T on Cat6. Also, remember that fiber standards have different distance capabilities.

Why candidates pick the wrong answer

B

Candidates often assume Cat6 supports 10 Gbps at full 100 meters, but IEEE specifies a shorter distance for 10 Gbps.

1288
MCQhard

Refer to the exhibit. An engineer configured PortFast on interface GigabitEthernet0/1, which connects to a server that does not participate in spanning tree. However, the port remains in the listening state for the full forward delay period before transitioning to forwarding. The engineer issues the show spanning-tree vlan 10 detail command. Based on the output, what is the most likely cause?

A.The port is configured as a trunk, so PortFast is not active.
B.BPDU Guard is enabled on the port, causing it to block.
C.The forward delay timer is set too high, and PortFast cannot override it.
D.The server is sending BPDUs, causing the port to lose its PortFast state.
AnswerA

PortFast is only effective on access ports. The exhibit shows ‘Edge port: no (default) portfast: no (default)’ despite the engineer enabling PortFast, indicating the port is operating as a trunk (or not an access port). Therefore, PortFast has no effect and the normal STP listening/learning states apply.

Why this answer

PortFast is designed to immediately transition a port to the forwarding state, bypassing the listening and learning states. However, PortFast is only effective on access ports; if the interface is configured as a trunk port, PortFast is automatically disabled by the switch. The output of 'show spanning-tree vlan 10 detail' would confirm the port is a trunk, explaining why it still goes through the full forward delay.

Exam trap

Cisco often tests the misconception that PortFast works on any port type, but the trap here is that PortFast is only effective on access ports, and trunk ports automatically disable PortFast regardless of configuration.

Why the other options are wrong

B

The port is not in an err-disabled state; BPDU Guard causes the port to be shut down, not to stay in listening.

C

Misunderstanding that PortFast bypasses timers completely on access ports; the high forward delay is irrelevant if PortFast were active.

D

The assumption that the server is sending BPDUs is contradicted by the output showing zero BPDUs received.

1289
Drag & Dropmedium

Drag and drop the following steps into the correct order to configure and recover from a BPDU guard violation on a PortFast-enabled access port in RSTP.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

Configure PortFast and BPDU guard on the access port. Then trigger a violation by connecting an unauthorized switch, which causes the port to error-disable. Diagnose by checking the error-disabled status.

To recover, first remove the offending device, then cycle the port with shutdown and no shutdown; otherwise the port will immediately go error-disabled again.

Exam trap

Do not confuse the order: configuration must precede the violation. Also, recovery requires removing the rogue switch before bouncing the interface; failing to do so will cause the port to trip again.

1290
MCQhard

A router has the following routes in its table: 172.16.0.0/16, 172.16.20.0/24, and 172.16.20.128/25. Which route is used for traffic to 172.16.20.200?

A.172.16.0.0/16
B.172.16.20.0/24
C.172.16.20.128/25
D.The default route
AnswerC

The destination IP 172.16.20.200 falls within the subnet 172.16.20.128/25 (range 172.16.20.128 to 172.16.20.255). According to the longest prefix match rule, this route has a prefix length of 25, which is longer (more specific) than the other candidate routes (default /0 and 172.16.0.0/16 /16), so it is preferred. The route 172.16.20.0/24 also matches but is less specific because /24 is shorter than /25. Thus, the router forwards the packet using the /25 route.

Why this answer

The /25 route is used because it is the most specific match. In plain language, the router looks for the narrowest route that still contains the destination address. Since 172.16.20.200 falls inside 172.16.20.128/25, that route wins over the broader /24 and /16 entries.

This is a direct longest-prefix-match question. It is meant to reinforce that specificity comes first in routing-table lookup. Broader routes remain useful, but they are not chosen when a more precise matching entry exists.

Exam trap

A frequent exam trap is selecting a broader subnet route such as 172.16.20.0/24 or 172.16.0.0/16 instead of the more specific 172.16.20.128/25. Candidates may mistakenly believe that any matching route is acceptable or that larger subnets are preferred. This misunderstanding ignores the fundamental longest prefix match rule used by Cisco routers, which always prioritizes the most specific route.

Falling for this trap leads to incorrect routing decisions and exam errors.

Why the other options are wrong

A

172.16.0.0/16 is the least specific route covering a large address range. Although it matches the destination IP, it is overridden by more specific routes with longer subnet masks, so it is not used.

B

172.16.20.0/24 is more specific than the /16 but less specific than the /25 route. Since the destination IP falls within the /25 subnet, the router prefers the /25 route over this /24.

D

The default route is only used when no other routes match the destination IP. Since multiple specific routes exist that match the destination, the default route is not selected.

When would these options actually be correct?

A

In a different scenario where the routing table only contains the route 172.16.0.0/16 and no more specific routes, any traffic destined for 172.16.20.200 would be routed using this option, making it the correct answer.

B

In a different scenario where the routing table only includes 172.16.20.0/24 and no more specific routes, a question asking which route would be used for traffic to 172.16.20.200 would correctly identify option B as the answer, since it would be the only applicable route.

D

If the question specified that the router had no specific routes for the 172.16.20.200 address and only a default route was configured, then the default route would be the correct answer. For example, if the routing table only contained a default route and no other specific routes.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of subnetting, thinking that a broader route would always be applicable, especially if they overlook the importance of specificity in routing decisions.

B

Candidates might choose this option because they recognize that 172.16.20.0/24 covers the target IP address, leading them to mistakenly assume it is the most appropriate route without considering the specificity of the other routes.

D

Candidates might choose the default route because they may assume that if no specific match is found, the default route is automatically used, reflecting a common misunderstanding of route specificity in routing tables.

1291
MCQeasy

Which STP role identifies the port on a non-root switch that has the best path back to the root bridge?

A.Designated port
B.Root port
C.Alternate port
D.Disabled port
AnswerB

The root port is the single port on a non-root switch that has the lowest root path cost to the root bridge, making it the switch's best path toward the root. It is determined by examining received BPDUs, comparing root path cost, then sender bridge ID, then sender port ID. This port is placed in the forwarding state and is the only port that actively forwards traffic toward the root, ensuring a loop-free topology.

Why this answer

The root port is the single port on a non-root switch that provides the lowest-cost path toward the root bridge. Designated ports forward away from the root for a segment, and alternate ports are backup paths.

Exam trap

A frequent exam trap is mistaking the designated port for the root port. While both forward traffic, the designated port is selected per LAN segment to forward frames away from the root bridge, not necessarily providing the best path back to the root. Another trap is confusing the alternate port with the root port; alternate ports are backup paths kept in blocking state and do not forward traffic unless the root port fails.

Candidates often overlook that the root port is unique per non-root switch and always represents the lowest-cost path to the root bridge, which is the key to answering this question correctly.

Why the other options are wrong

A

Designated ports are selected for each LAN segment to forward traffic away from the root bridge, but they do not represent the best path back to the root bridge on a non-root switch. Therefore, this option is incorrect.

C

Alternate ports serve as backup paths and remain in a blocking state unless the root port fails. They do not identify the best path back to the root bridge, so this option is incorrect.

D

Disabled ports do not participate in STP forwarding or path selection and are not related to identifying the best path back to the root bridge, making this option incorrect.

When would these options actually be correct?

A

In a question asking for the port role on a switch that connects to the root bridge and is responsible for forwarding traffic towards it, the designated port would be the correct answer. For example, if the question stated, 'Which port role on a switch connects to the root bridge and forwards traffic towards it?' then the designated port would be correct.

C

In a question asking about the role of ports in a Rapid Spanning Tree Protocol (RSTP) environment, the alternate port could be identified correctly if the question specifies a scenario where a switch has multiple paths to the root bridge and is asked to identify ports that can be activated if the primary path fails.

D

In a different question asking which port state is used for troubleshooting or configuration purposes, a scenario might involve a network administrator needing to identify ports that are intentionally disabled for security reasons. In that context, 'disabled port' could be the correct answer.

Why candidates pick the wrong answer

A

Candidates may confuse the designated port with the root port due to their roles in STP, as both are involved in determining the best path for traffic. Additionally, the term 'designated' may sound authoritative, leading candidates to believe it is the correct choice.

C

Candidates may confuse the alternate port with the root port due to their similar roles in providing redundancy and may mistakenly believe that any port that provides an alternative path qualifies as the best path.

D

Candidates may confuse 'disabled port' with other port roles due to a lack of understanding of STP states, thinking that any non-operational port might still have relevance in the context of network topology.

1292
MCQhard

A router has a directly connected route to 10.1.1.0/24 and a static default route. Which route is used for traffic to 10.1.1.200?

A.The directly connected 10.1.1.0/24 route
B.The static default route
C.Both routes equally
D.Neither route
AnswerA

The directly connected 10.1.1.0/24 route is selected because routers perform a longest prefix match when forwarding packets. The destination 10.1.1.1 falls within the 10.1.1.0/24 subnet, which has a 24-bit prefix, making it more specific than any default route. Since the connected route is present in the routing table, it takes precedence over less specific routes.

Why this answer

The directly connected route is used because it is the most specific and most immediate match. In practical terms, the router already knows that 10.1.1.200 belongs to a network on one of its own interfaces, so there is no reason to use the default route. The default route exists only for destinations that do not match anything more specific.

This is one of the most fundamental route-selection behaviors in IP routing.

Exam trap

A frequent exam trap is selecting the static default route for traffic destined to an IP address within a directly connected subnet. Candidates might incorrectly believe the default route overrides connected routes due to its static configuration or because it is manually set. However, the router always prefers the most specific route, which is the directly connected subnet in this case.

Misunderstanding the longest prefix match and administrative distance hierarchy leads to this error. Remember, the default route is only a fallback when no other route matches the destination IP address.

Why the other options are wrong

B

This option is incorrect because the static default route is less specific (0.0.0.0/0) and only used when no other route matches the destination. Since a connected route exists, the default route is ignored.

C

This option is wrong because routing does not load balance between a directly connected route and a static default route. The router selects the single best route based on prefix length and administrative distance.

D

This option is incorrect because the router clearly has a matching directly connected route for 10.1.1.200. Therefore, it will use that route rather than discarding both or failing to forward.

When would these options actually be correct?

B

If the question stated that the router had no directly connected routes and only a static default route configured to route all traffic, then the static default route would be the correct answer for traffic to 10.1.1.200.

C

In a different scenario where both routes have the same administrative distance and the router is configured to load balance traffic, a question might ask which routes are used for traffic to a specific destination. In that case, both routes could be considered equally valid for routing decisions.

D

In a different scenario where the router has no directly connected routes and only a static default route configured, a question asking about traffic to an unreachable IP address (e.g., 10.2.2.200) would make this option correct, as the default route would be the only available path.

Why candidates pick the wrong answer

B

Candidates may mistakenly believe that the default route is a catch-all for all traffic, leading them to choose it without considering the specificity of the directly connected route that applies in this scenario.

C

Candidates may choose this option due to a misunderstanding of routing priorities, thinking that multiple routes can be used simultaneously without recognizing that directly connected routes take precedence.

D

Candidates may choose this option if they mistakenly believe that a default route is always used when a specific route is not explicitly defined, overlooking the presence of a directly connected route.

1293
PBQhard

You are connected to R1 via the console. R1 is a newly deployed router that connects two subnets: 192.168.1.0/24 on GigabitEthernet0/0 and 192.168.2.0/24 on GigabitEthernet0/1. There is a default route to the Internet via ISP router at 203.0.113.1, but the network policy requires that traffic from 192.168.1.0/24 to the Internet must exit via a different next-hop 203.0.113.2. You need to implement policy-based routing on R1 to forward traffic from source 192.168.1.0/24 to 203.0.113.2, while all other traffic uses the default route via 203.0.113.1.

Hints

  • Policy-based routing uses route-maps applied to incoming interfaces.
  • The route-map matches traffic using an access list and sets the next-hop.
  • Verify the route-map and its application on the correct interface.
A.Create an access list matching source 192.168.1.0/24, a route-map with set ip next-hop 203.0.113.2, and apply the route-map inbound on GigabitEthernet0/0.
B.Create an access list matching source 192.168.1.0/24, a route-map with set ip next-hop 203.0.113.2, and apply the route-map outbound on GigabitEthernet0/1.
C.Create an access list matching destination 203.0.113.2, a route-map with set ip next-hop 203.0.113.2, and apply the route-map inbound on GigabitEthernet0/0.
D.Configure a static route for 192.168.1.0/24 with next-hop 203.0.113.2 and rely on the default route for other traffic.
AnswerA
solution
! R1
access-list 101 permit ip 192.168.1.0 0.0.0.255 any
route-map PBR permit 10
match ip address 101
set ip next-hop 203.0.113.2
interface GigabitEthernet0/0
ip policy route-map PBR

Why this answer

Policy-based routing (PBR) allows overriding the routing table for specific traffic. The access list identifies traffic from 192.168.1.0/24, the route-map sets the next-hop to 203.0.113.2, and applying it to the incoming interface G0/0 ensures that traffic entering from that subnet follows the policy.

Exam trap

Remember that PBR is applied inbound on the interface receiving the traffic, not outbound. Also, the access list in PBR matches traffic based on the criteria you want to override (source, destination, etc.), not the next-hop address. Static routes are destination-based and cannot be used to forward based on source address.

Why the other options are wrong

B

PBR must be applied inbound on the interface receiving the traffic, not outbound on the exit interface.

C

PBR uses the access list to match traffic based on source, destination, or other criteria; here the requirement is to match source subnet.

D

A static route controls forwarding based on destination, not source. Policy-based routing is needed to forward based on source address.

Why candidates pick the wrong answer

B

Candidates may think PBR is applied on the exit interface because it affects forwarding, but the correct application is inbound.

C

Candidates might confuse the matching criteria and think they need to match the next-hop address as a destination.

D

Candidates may think a static route can be used to direct traffic from a specific source, but static routes are destination-based.

1294
Multi-Selectmedium

Which two statements accurately describe the role of a switch MAC address table?

Select 2 answers
A.It maps learned MAC addresses to switch ports for local forwarding decisions.
B.It helps reduce unnecessary flooding when the destination MAC is known.
C.It stores the best Layer 3 routes to remote networks.
D.It contains the router’s OSPF authentication keys.
E.It assigns IP addresses to end hosts dynamically.
AnswersA, B

A switch builds its MAC address table by examining the source MAC addresses of incoming frames and associating them with the ingress port. This learned mapping is then used to make local forwarding decisions, allowing the switch to deliver frames directly to the port associated with the destination MAC address. This is the fundamental operation of Layer 2 switching.

Why this answer

A switch MAC address table helps the switch make local forwarding decisions efficiently. In plain language, the switch learns which MAC addresses appear on which ports and then uses that information to send frames only where they need to go instead of flooding every frame everywhere.

The MAC table is not the same thing as a routing table, and it is not used for OSPF neighbor storage or DHCP lease records.

Exam trap

Avoid confusing the MAC address table with routing tables or ARP tables, which involve IP addresses and routing information.

Why the other options are wrong

C

This option is wrong because a switch MAC address table does not store Layer 3 routing information; it specifically maps Layer 2 MAC addresses to switch ports for local traffic forwarding.

D

Option D is incorrect because a switch MAC address table does not store OSPF authentication keys; it is designed to map MAC addresses to switch ports for forwarding decisions within a Layer 2 network.

E

This option is wrong because a switch MAC address table does not handle IP address assignments; it specifically deals with mapping MAC addresses to switch ports for local traffic forwarding.

When would these options actually be correct?

C

This option would be correct in a question that asks about the functions of a router's routing table, which does store the best Layer 3 routes to remote networks based on various routing protocols.

D

In a question focused on router configurations, if asked about the components of OSPF and their roles, option D could be correct if it specifically inquires about where OSPF authentication keys are stored within a router's configuration.

E

In a question asking about DHCP functionality, such as 'What mechanism is used to assign IP addresses dynamically to end hosts on a network?', option E would be correct as it directly relates to the role of DHCP servers in IP address allocation.

Why candidates pick the wrong answer

C

Candidates might choose this option due to confusion between Layer 2 and Layer 3 functionalities, as both involve addressing but serve different purposes in network operations.

D

Candidates may find this option tempting due to a misunderstanding of the roles of different network devices, confusing the functions of switches and routers, especially in the context of routing protocols like OSPF.

E

Candidates may find this option tempting due to the association of switches with network connectivity and the common misconception that switches also manage IP address assignments, leading to confusion between Layer 2 and Layer 3 functionalities.

1295
PBQhard

You are connected to R1, a multilayer switch acting as the STP root for VLAN 10. Configure Root Guard on port GigabitEthernet0/1 (designated port) to protect against superior BPDUs from an unauthorized switch, Loop Guard on uplink GigabitEthernet0/2 to prevent loops, and BPDU Guard on PortFast-enabled GigabitEthernet0/3. After configuration, a superior BPDU arrives on G0/1, blocking the port; verify the Root Guard state and ensure BPDU Guard triggers err-disable on G0/3.

Network Topology
G0/1: designated portG0/2: uplinkG0/3: PortFastR1Access SwitchCore SwitchEnd Device

Hints

  • Root Guard is applied on ports that should never become root; use 'spanning-tree guard root'.
  • Loop Guard prevents alternate or root ports from becoming designated when BPDUs stop; use 'spanning-tree guard loop' on uplinks.
  • BPDU Guard combined with PortFast err-disables a port upon BPDU reception; enable with 'spanning-tree bpduguard enable' under the interface.
A.G0/1 is in root-inconsistent state; G0/3 is in err-disabled state.
B.G0/1 is in blocking state; G0/3 is in err-disabled state.
C.G0/1 is in root-inconsistent state; G0/3 is in blocking state.
D.G0/1 is in err-disabled state; G0/3 is in root-inconsistent state.
AnswerA
solution
! R1
interface GigabitEthernet0/1
spanning-tree guard root
interface GigabitEthernet0/2
spanning-tree guard loop
interface GigabitEthernet0/3
spanning-tree bpduguard enable

Why this answer

Root Guard is needed on the designated port (G0/1) to prevent an unauthorized switch from becoming root by sending superior BPDUs. Loop Guard on the uplink (G0/2) prevents loops if BPDUs stop arriving. BPDU Guard on PortFast ports (G0/3) immediately err-disables them upon BPDU reception.

The configuration uses 'spanning-tree guard root' on G0/1, 'spanning-tree guard loop' on G0/2, and 'spanning-tree bpduguard enable' on G0/3. Verification shows G0/1 blocked by root-inconsistent state and G0/3 in err-disabled state.

Exam trap

Do not confuse the states caused by Root Guard (root-inconsistent) and BPDU Guard (err-disable). Also, remember that Root Guard is applied to designated ports, not root or alternate ports.

Why the other options are wrong

B

Root Guard uses a specific 'root-inconsistent' state, not the generic 'blocking' state.

C

BPDU Guard triggers err-disable, not blocking. Blocking is an STP state, not an error state.

D

Root Guard and BPDU Guard have different effects: root-inconsistent vs. err-disable. Mixing them up is a common error.

Why candidates pick the wrong answer

B

Candidates may confuse the root-inconsistent state with the standard STP blocking state, as both prevent traffic forwarding.

C

Candidates might think BPDU Guard puts the port into a non-forwarding STP state like blocking, but it actually disables the port entirely.

D

Candidates may confuse the two guard features, especially since both are STP protection mechanisms.

1296
MCQhard

A subnet uses the mask 255.255.255.224. How many usable host addresses does it provide?

A.14
B.30
C.62
D.126
AnswerB

The subnet mask 255.255.255.224 equates to a /27 prefix, which leaves only 3 bits for host addressing in the final octet. With 5 host bits total, the block contains 2^5 = 32 addresses. Subtracting the network and broadcast addresses yields exactly 32 - 2 = 30 usable host addresses.

Why this answer

A mask of 255.255.255.224 corresponds to a /27 prefix. In plain language, that leaves 5 host bits available in the address, which creates 32 total addresses in each subnet. Two of those are reserved: one for the network address and one for the broadcast address. That leaves 30 usable host addresses.

This is a classic subnetting question because it tests whether you can move from mask to prefix idea to host count without getting lost. Many learners remember the block size but forget to subtract the network and broadcast entries. The correct answer comes from that full logic chain: /27 means 32 total, and therefore 30 usable.

Exam trap

Remember to subtract the network and broadcast addresses from the total count of addresses in a subnet.

Why the other options are wrong

A

This option is wrong because a subnet mask of 255.255.255.224 provides 30 usable host addresses, not 14. The calculation is based on the formula 2^(number of host bits) - 2, where the number of host bits is 5 for this subnet mask.

C

This option is wrong because a subnet mask of 255.255.255.224 allows for 32 total addresses, of which 30 are usable after subtracting the network and broadcast addresses. The calculation is 2^(32-27) - 2 = 30 usable addresses.

D

Option D is incorrect because a subnet mask of 255.255.255.224 allows for 30 usable host addresses, not 126. The calculation is based on the formula 2^(32 - subnet bits) - 2, where the subnet bits for this mask is 27.

When would these options actually be correct?

A

This option would be correct in a scenario where the question specifies a subnet mask of 255.255.255.240, which allows for 14 usable host addresses. In this case, the calculation would be 2^(4) - 2 = 14.

C

If the question asked about a subnet mask of 255.255.255.192 instead, which provides 62 usable addresses, then option C would be the correct answer. In this case, the calculation would be 2^(32-26) - 2 = 62 usable addresses.

D

If the question asked how many usable addresses are in a subnet with a mask of 255.255.255.0, which allows for 256 total addresses minus 2 for the network and broadcast addresses, then option D would be correct as it would provide 254 usable addresses.

Why candidates pick the wrong answer

A

Candidates may choose this option due to confusion between different subnet masks and their corresponding usable addresses, particularly if they miscalculate or misremember the formula for determining usable hosts.

C

Candidates may choose this option due to confusion between subnet sizes and their corresponding usable addresses, especially if they have recently studied larger subnets and misapplied the calculations.

D

Candidates may choose this option due to confusion with larger subnet sizes, mistakenly associating the number 126 with a common subnet size, or miscalculating the usable hosts based on a misunderstanding of subnetting principles.

1297
MCQhard

Refer to the exhibit. A network engineer is verifying OSPF routing on R1. All routers in the topology are expected to reside in OSPF area 0, and the network 172.16.0.0/16 should be advertised from R2 within the same area. The engineer issues the show ip route 172.16.0.0 command on R1 and sees the output in the exhibit. The engineer expected to see an intra-area route (O) instead of an inter-area route (O IA). What is the most likely cause of this discrepancy?

A.R1 has a mismatched OSPF process ID compared to the ABR.
B.The network type on GigabitEthernet0/0 is configured as non-broadcast, preventing full adjacency.
C.The metric for the route is too high, causing OSPF to treat it as an inter-area route.
D.The destination network 172.16.0.0/16 is located in a different OSPF area.
AnswerD

The routing table entry shows 'type inter area'. This indicates the prefix is being learned via an OSPF Type-3 summary LSA, which is only generated when the network is in a different area than the local router. Therefore, the network is indeed in a different area, contradicting the assumption that R1 and the destination are both in area 0.

Why this answer

The route 172.16.0.0/16 appears as O IA (inter-area) on R1, which means R1 learned it via a Type 3 LSA from an ABR. For the route to be intra-area (O), the destination network must reside in the same OSPF area (area 0) as R1. Since R2 is advertising this network, if it were truly in area 0, R1 would see an O route.

The O IA designation indicates that the network is in a different area, likely because R2's interface connected to 172.16.0.0/16 is configured in a different OSPF area, or R2 is acting as an ABR.

Exam trap

Cisco often tests the distinction between intra-area and inter-area OSPF routes, and the trap here is that candidates mistakenly think a high metric or mismatched process ID can change the route type, when in fact only the area configuration determines whether a route is O or O IA.

Why the other options are wrong

A

Candidates mistakenly assume that OSPF process IDs must match globally for proper LSA exchange, but they are only locally significant.

B

Candidates may think that the network type influences the OSPF LSA type, but it only affects neighbor discovery and DR/BDR election, not the area origin of LSAs.

C

Candidates sometimes confuse the metric influence with the route type, thinking that OSPF converts routes when the cost exceeds a threshold.

1298
MCQhard

A standard ACL and an extended ACL are both available for a design. Which requirement most strongly indicates that an extended ACL is needed?

A.The policy must distinguish traffic by destination, protocol, or port.
B.The policy needs to match only one source subnet.
C.The ACL must be placed near the destination.
D.The network uses IPv6 instead of IPv4.
AnswerA

A standard ACL identifies traffic solely by source IPv4 address, so any policy that must differentiate flows by destination address, protocol number, or TCP/UDP port is impossible with a standard ACL. Extended access lists (100–199 and 2000–2699) are required because they evaluate source, destination, protocol, and port fields. Thus, this criterion forces the extended ACL choice.

Why this answer

An extended ACL is most strongly indicated when the policy must match not just on source address, but also on destination, protocol, or port information. In practical terms, if the requirement is something like “block HTTP but allow SSH” or “deny traffic to one server but not another,” a standard ACL is too limited because it mainly matches only the source. Option B (matching only one source subnet) can be done with a standard ACL, so it does not demand an extended ACL.

Option C (placement near destination) is a guideline for standard ACLs, not a reason to choose an extended ACL. Option D (IPv6) is irrelevant because the scenario explicitly states both ACL types are available and standard ACLs do not exist for IPv6—this question is about IPv4 ACLs.

Exam trap

Remember that standard ACLs can only filter based on source IP addresses. If the requirement involves protocols or ports, think extended ACL.

Why the other options are wrong

B

Matching only one source subnet can be accomplished with a standard ACL, so this does not strongly indicate a need for an extended ACL.

C

Placing an ACL near the destination is a characteristic of standard ACLs, not a criterion that selects an extended ACL.

D

The scenario assumes both standard and extended ACLs are available; standard ACLs do not exist for IPv6, so this requirement does not apply to the IPv4 ACL choice.

When would these options actually be correct?

B

In a different scenario, if the exam question specifically states that the requirement is to implement a simple access control that only needs to allow or deny traffic from a single source subnet to a specific destination, then option B would be the correct choice.

C

In a scenario where a question asks about the most effective ACL placement strategy for managing traffic flows to a specific server, stating that the ACL must be placed near the destination could be correct if the focus is on minimizing unnecessary traffic across the network.

D

In a different scenario, if the question asked about the necessity of ACLs for a network exclusively using IPv6, and the focus was on matching traffic based on IPv6-specific features, then this option could be correct, as extended ACLs are often used in IPv6 environments.

Why candidates pick the wrong answer

B

Candidates may find this option tempting because it suggests a straightforward requirement that seems manageable with a standard ACL, leading them to overlook the need for more detailed traffic filtering capabilities that extended ACLs provide.

C

Candidates may find this option tempting because they understand that placement can impact performance and security, leading them to believe that it is a critical factor in determining the type of ACL needed.

D

Candidates may find this option tempting because they might associate IPv6 with advanced filtering needs, leading them to believe that it inherently requires extended ACLs, without considering the specific requirements of the question.

1299
MCQhard

R1 and R2 are connected via a shared Ethernet segment. Both routers are configured in OSPF area 0 and are on the same IP subnet. OSPF authentication is enabled on both interfaces, but the adjacency is not forming. What is the most likely reason?

A.The OSPF authentication key does not match on the two routers.
B.The routers must use different OSPF areas to become neighbors.
C.OSPF message-digest authentication can be used only on serial links.
D.The routers must remove IP addressing before OSPF can form.
AnswerA

OSPF interfaces configured with an authentication key must match the key and key ID on neighboring routers. When R1 sends a Hello packet, it computes an authentication hash using its configured key; R2 verifies that value with its own key. A mismatch causes the receiving router to silently drop the Hello, so no adjacency can form even though all other OSPF parameters are correct.

Why this answer

The most likely reason is an OSPF authentication mismatch. In practical terms, both routers are on the same IP subnet and in the same area, but they are not using the same authentication key on the shared link. OSPF neighbors must agree on key authentication parameters before they will trust each other enough to form an adjacency.

This is a classic CCNA troubleshooting pattern because the configuration looks almost correct until you compare the security settings carefully.

Exam trap

A frequent exam trap is selecting an answer that incorrectly states OSPF authentication is limited to serial links or that routers must be in different areas to form adjacency. Candidates may also mistakenly believe that removing IP addressing is necessary for OSPF to form. These misconceptions overlook that OSPF authentication applies to Ethernet interfaces and that neighbors must be in the same area and subnet with matching authentication keys.

Misreading these details leads to choosing incorrect options that seem plausible but contradict OSPF adjacency rules.

Why the other options are wrong

B

This option is incorrect because OSPF neighbors must be in the same area to form adjacency. Using different areas on the same segment prevents adjacency, so this option contradicts OSPF area rules.

C

This option is incorrect because OSPF authentication, including message-digest (MD5), is supported on Ethernet interfaces, not just serial links. Authentication is not limited by interface type.

D

This option is incorrect because OSPF requires valid IP addressing on interfaces to operate. Removing IP addressing disables OSPF on that link, so adjacency cannot form without IP addresses.

When would these options actually be correct?

B

In a different scenario where the question specifies that R1 and R2 are configured in different OSPF areas, the option would be correct. For example, if the question stated that R1 is in area 0 and R2 is in area 1, this option would accurately reflect the requirement for OSPF adjacency.

C

In a different question setup where the context specifies that OSPF message-digest authentication is only applicable to serial links, a scenario could involve two routers connected via a serial link attempting to authenticate with message-digest but failing due to incorrect configuration. In this case, the option would be correct.

D

In a different question, if it were stated that the routers were configured to use a specific OSPF feature that required no IP addressing for a unique setup, such as a lab environment simulating a non-IP OSPF scenario, then this option could be correct.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of OSPF area configurations, believing that adjacency can only occur between routers in different areas, which is a common misconception among those new to OSPF.

C

Candidates may find this option tempting due to a misunderstanding of OSPF authentication types and their applicability, leading them to incorrectly associate message-digest authentication with specific link types.

D

Candidates might choose this option due to a misunderstanding of OSPF requirements, confusing the need for proper IP addressing with the adjacency formation process, leading them to believe that removing IP addresses could somehow resolve adjacency issues.

1300
MCQmedium

R3 has the static route 'ip route 172.20.8.0 255.255.255.0 192.168.1.1'. Packets destined for 172.20.8.0/24 are being dropped. What is the most likely cause?

A.The destination network mask should be /16 instead of /24
B.The next-hop address is not reachable from R3
C.Static routes require an outbound access list
D.The route must use administrative distance 255
AnswerB

The static route is invalid because R3 cannot resolve the specified next-hop address. A static route with a next-hop IP requires that the next-hop be reachable via a directly connected network or another valid route in the routing table; otherwise, the route is not installed. Since the next-hop is unreachable, packets cannot be forwarded and the route remains inactive.

Why this answer

A static route can only work if the next-hop address is reachable. If the next hop is down or missing from the routing table, the route cannot forward traffic successfully.

Exam trap

A frequent exam trap is assuming that an incorrect subnet mask on the static route causes packets to be dropped. While subnet masks affect routing accuracy, they do not cause next-hop reachability failures. Another trap is believing that static routes require outbound ACLs, which is false; ACLs control traffic filtering but do not impact static route functionality.

Additionally, some may think setting the administrative distance to 255 is necessary for static routes, but this actually disables the route, making it unusable. The key mistake is overlooking the requirement that the next-hop IP address must be reachable for the static route to work, which is the actual cause of packet drops in this scenario.

Why the other options are wrong

A

Option A suggests changing the destination network mask from /24 to /16. While subnet masks must be correct for proper routing, an incorrect mask does not cause next-hop reachability issues or packet drops due to unreachable next-hop addresses. The problem here is related to next-hop reachability, not the destination mask.

C

Option C incorrectly states that static routes require an outbound access list. Static routes do not need ACLs to function; ACLs are used for traffic filtering and security policies, not for enabling or disabling static routes. This option is invalid.

D

Option D claims the route must use administrative distance 255. Administrative distance 255 actually makes a route unusable, so setting it to 255 would prevent the static route from working. The default administrative distance for static routes is 1, which is preferred over most dynamic routes.

When would these options actually be correct?

A

In a different scenario where a static route is configured for a subnet that should indeed be larger, such as 172.20.0.0/16, a candidate might be asked to identify if the subnet mask is incorrectly set, making /16 the correct choice for proper routing.

C

In a different question, if the context specifies that a static route is being used in a network where security policies are enforced through access lists, and the question asks about the configuration of static routes under such constraints, then this option could be correct.

D

In a different question setup where a static route is configured with an administrative distance of 255, the question might ask why the route is not being used. In that case, the correct answer would be that the route is effectively disabled due to the administrative distance being set to 255.

Why candidates pick the wrong answer

A

Candidates may confuse subnetting concepts and assume that a larger subnet mask would resolve routing issues, leading them to incorrectly believe that adjusting the mask would fix the packet drop problem.

C

Candidates may confuse static routes with dynamic routing protocols, which often utilize access lists for filtering. This misunderstanding can lead them to incorrectly believe that access lists are a requirement for static routes.

D

Candidates may find this option tempting because they might confuse administrative distance settings with route reachability, thinking that a high administrative distance could be a reason for packet drops.

1301
MCQhard

A user connects a Cisco IP Phone with a PC attached to the phone's PC port to switch interface GigabitEthernet0/5. The PC obtains an IP address and can reach the network, but the phone displays "Configuring IP" and never registers. Based on the exhibit outputs, what is the most likely cause?

A.The switchport must be configured as a trunk to support voice VLANs.
B.VLAN 20 has not been created in the switch's VLAN database.
C.The native VLAN on the trunk ports between the switch and the DHCP server is incorrectly set to VLAN 10.
D.The phone is manually configured to use VLAN 10 for voice traffic instead of VLAN 20.
AnswerB

The 'show vlan brief' output lists only VLANs 1 and 10. VLAN 20 does not exist, so the switch discards any tagged frames arriving on the port with VLAN ID 20, causing the phone's DHCP/TFTP communication to fail.

Why this answer

The PC obtains an IP address and can reach the network, indicating that the access VLAN (likely VLAN 1 or the native VLAN) is functioning. However, the phone displays 'Configuring IP' and never registers, which means it cannot obtain an IP address on its voice VLAN. The most likely cause is that VLAN 20, which is configured as the voice VLAN on the switchport, has not been created in the switch's VLAN database.

Without the VLAN existing, the switch cannot forward traffic or DHCP requests for that VLAN, leaving the phone stuck in the IP configuration phase.

Exam trap

Cisco often tests the distinction between configuring a voice VLAN on an interface and actually creating that VLAN in the global VLAN database; candidates mistakenly assume that referencing a VLAN in interface configuration automatically creates it.

Why the other options are wrong

A

Voice VLANs operate on access ports by tagging voice traffic while keeping PC traffic untagged in the data VLAN. A trunk is not required.

C

Native VLAN mismatches on trunks would affect both data and voice VLANs if both were allowed. The PC works, ruling out a general trunk issue.

D

The phone would work if it was sending voice traffic on the data VLAN (10), because VLAN 10 exists. The phone failing indicates a missing voice VLAN, not a misconfiguration on the phone.

1302
MCQhard

Why is the combination of strong authentication and centralized logging generally better than using either one alone?

A.Authentication helps prevent unauthorized access, while centralized logging improves visibility and investigation.
B.They are redundant because both perform exactly the same function.
C.Centralized logging makes authentication unnecessary.
D.Strong authentication removes the need for device event records.
AnswerA

This is correct because the two controls complement each other.

Why this answer

The combination is better because strong authentication helps prevent unauthorized access, while centralized logging helps detect, review, and investigate activity across the environment. In plain language, one control focuses more on prevention, while the other improves visibility and accountability. Together they create a stronger security posture than either one alone.

This is an important design mindset. Security is stronger when controls complement each other instead of trying to solve every problem with one mechanism. The correct answer is the one focused on prevention plus visibility.

Exam trap

Avoid assuming that two controls can cover all security needs or that combining them simplifies architecture.

Why the other options are wrong

B

Option B is incorrect because strong authentication and centralized logging serve distinct functions; authentication secures access while logging tracks and analyzes events, enhancing security and compliance.

C

This option is incorrect because centralized logging does not eliminate the need for authentication; both are essential for a comprehensive security posture. Authentication verifies user identity, while logging tracks access and actions for auditing and incident response.

D

This option is wrong because strong authentication does not eliminate the need for device event records; both are essential for comprehensive security management. Device event records provide critical insights into system activity, which strong authentication alone cannot address.

When would these options actually be correct?

B

In a question that asks about redundancy in security measures, where both strong authentication and centralized logging are framed as overlapping in function, option B could be correct if the context implies they provide similar protective benefits without additional layers.

C

In a scenario where a question asks if centralized logging can replace authentication in a specific context, such as a highly controlled environment where all users are trusted, this option could be considered correct. For example, if the question specifies a system that only allows access through a secure VPN with no external access, one might argue that logging alone suffices.

D

In a scenario where the exam question asks if strong authentication alone can ensure complete security without any logging, option D could be correct. If the question emphasizes that strong authentication is sufficient for security, then it could imply that device event records are unnecessary.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of security principles, believing that multiple security measures can be redundant rather than complementary, leading to confusion about their distinct roles.

C

Candidates may choose this option due to a misunderstanding of the roles of authentication and logging, believing that logging can inherently provide sufficient security without user verification.

D

Candidates may choose this option due to a misunderstanding of security principles, believing that robust authentication alone suffices for security oversight, thus overlooking the importance of logging for accountability and forensic analysis.

1303
MCQmedium

What is an autonomous system in basic BGP terminology?

A.A collection of networks and routers under common administrative routing control
B.A single switch VLAN
C.A specific OSPF area inside one router
D.A type of wireless access point
AnswerA

In BGP terminology, an autonomous system (AS) is a set of routers and networks that operate under a single administrative domain and present a consistent routing policy to other ASes. It is identified by a globally unique AS number (ASN) and exchanges reachability information with external peers via BGP, making it the fundamental unit of inter-domain routing.

Why this answer

An autonomous system is a collection of IP networks and routers under a common routing policy or administrative control. In practical terms, it is the domain boundary concept used in BGP discussions. BGP uses AS concepts to reason about routing between separate administrative networks.

This is one of the first BGP ideas learners need to understand.

Exam trap

A frequent exam trap is mistaking an autonomous system for a VLAN or an OSPF area. VLANs are Layer 2 broadcast domains and do not relate to routing domains or administrative control of routing policies. Similarly, OSPF areas segment a single routing domain to optimize routing but do not represent separate administrative entities.

Confusing these concepts can lead to incorrect answers because BGP’s autonomous system concept specifically refers to a collection of networks and routers under a common administrative routing policy, which is distinct from VLAN or OSPF area segmentation.

Why the other options are wrong

B

This option is incorrect because a VLAN is a Layer 2 segmentation method that isolates broadcast domains and does not relate to routing policies or autonomous systems in BGP.

C

This option is wrong since an OSPF area is a subdivision within a single routing domain to optimize routing, not an autonomous system representing separate administrative control.

D

This option is incorrect because an autonomous system is a routing domain concept, whereas a wireless access point is a physical device unrelated to BGP or routing domains.

When would these options actually be correct?

B

If the question were about defining network segments within a local area network (LAN) and asked for a term that describes a logical grouping of devices managed by a single switch, then 'a single switch VLAN' would be the correct answer.

C

If the question were to ask about the components of OSPF and how they relate to routing within a single organization, then 'a specific OSPF area inside one router' could be the correct answer, as it pertains to the organization of routing information within that context.

D

If the exam question asked for the definition of a wireless access point or its types, then option D would be correct. For example, a question could ask, 'Which of the following is a type of device used to extend a wireless network?'

Why candidates pick the wrong answer

B

Candidates may confuse the concept of an autonomous system with simpler network configurations, such as VLANs, leading them to select this option due to familiarity with basic networking concepts.

C

Candidates may choose this option due to confusion between routing protocols and their components, leading them to associate OSPF areas with broader routing concepts like autonomous systems.

D

Candidates may choose this option due to a misunderstanding of networking terminology, confusing BGP concepts with wireless networking devices, especially if they have encountered both topics in their studies.

1304
MCQhard

A host address is 10.100.12.94/26. Which address is the broadcast address for that subnet?

A.10.100.12.63
B.10.100.12.127
C.10.100.12.64
D.10.100.12.128
AnswerB

This is correct because .94 is in the 64-127 /26 range.

Why this answer

A /26 subnet has a block size of 64, so the fourth-octet ranges are 0–63, 64–127, 128–191, and 192–255. The host address 10.100.12.94 lies in the 64–127 range, making the broadcast address the last address in that range: 10.100.12.127. Option A (10.100.12.63) is the broadcast of the previous subnet (0–63).

Option C (10.100.12.64) is the network address of the subnet containing the host. Option D (10.100.12.128) is the network address of the next subnet (128–191).

Exam trap

Be careful not to confuse host addresses or network addresses with the broadcast address. Remember, the broadcast address is the last address in the subnet range.

Why the other options are wrong

A

10.100.12.63 is the broadcast address of the 0–63 subnet, not the one containing 94.

C

10.100.12.64 is the network address of the 64–127 subnet, not the broadcast.

D

10.100.12.128 is the network address of the 128–191 subnet, not the broadcast.

When would these options actually be correct?

A

In a question where the subnet mask is /26 and the network address is 10.100.12.0, if the question mistakenly states that the subnet ends at 10.100.12.63, then 10.100.12.63 would be the correct broadcast address for that defined range.

C

In a different question setup where the subnet mask is /26 and the network address is 10.100.12.64, option C would be the correct answer if the question asked for the first usable host address instead of the broadcast address.

D

If the question were to ask for the broadcast address of a subnet defined by 10.100.12.128/26, then option D would be correct, as the broadcast address for that subnet would be 10.100.12.191.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of subnetting, where they incorrectly calculate the broadcast address by only considering the last octet and not accounting for the subnet mask properly.

C

Candidates might choose option C due to confusion between the broadcast address and the first usable address in a subnet, especially if they miscalculate the range of addresses available in a /26 subnet.

D

Candidates may be tempted by option D because it is a common mistake to miscalculate subnet boundaries, especially when dealing with larger subnets or when they misinterpret the CIDR notation.

1305
PBQhard

You are connected to R1, a multilayer switch acting as a DNS client and DNS server for the local network. The network uses 192.168.1.0/24 for internal hosts. Users report that hostnames like 'server1.example.com' fail to resolve. Diagnose and fix the DNS resolution issue using nslookup and dig. Ensure that R1 can resolve both forward and reverse DNS queries correctly.

Network Topology
192.168.1.0/24G0/0203.0.113.0/30SiR1Internal HostsInternet

Hints

  • Check if the DNS forwarder is reachable; if not, you may need to configure local DNS records.
  • Use 'ip host' to create an A record, and 'ip dns primary' for reverse zone with PTR.
  • Remove the unreachable name-server with 'no ip name-server' to stop using it.
A.Configure R1 as a local DNS server with an A record for server1.example.com (192.168.1.10) and a PTR record for 192.168.1.10, then remove the unreachable forwarder 192.0.2.53 and ensure ip domain lookup uses the local server.
B.Configure R1 as a DNS server with only an A record for server1.example.com (192.168.1.10) and keep the forwarder 192.0.2.53 for other queries.
C.Remove the forwarder 192.0.2.53 and configure R1 as a DNS server with only a PTR record for 192.168.1.10.
D.Change the DNS forwarder to a reachable server like 8.8.8.8 and add a PTR record for 192.168.1.10 on R1.
AnswerA
solution
! R1
ip dns server
ip host server1.example.com 192.168.1.10
ip dns primary 1.168.192.in-addr.arpa soa ns.example.com admin.example.com 1 3600 900 604800 86400
ip dns primary 1.168.192.in-addr.arpa ns ns.example.com
ip dns primary 1.168.192.in-addr.arpa ptr 10 1.168.192.in-addr.arpa server1.example.com
no ip name-server 192.0.2.53

Why this answer

The issue is twofold: first, the DNS forwarder (192.0.2.53) is unreachable, causing forward lookups to fail with NXDOMAIN; second, there is no PTR record for the reverse lookup zone. The forward lookup failure is because R1 is configured to use an unreachable external DNS server. The reverse lookup failure is because no PTR record exists for the host IP.

To fix, either configure a reachable DNS forwarder or enable local DNS server with appropriate records. Here, we configure R1 as a local DNS server with an A record for 'server1.example.com' pointing to 192.168.1.10 and a PTR record for the reverse lookup. Then we remove the unreachable forwarder and ensure ip domain lookup uses local server.

Exam trap

Students often forget that reverse DNS requires a PTR record in addition to the A record. Also, they may not verify that the DNS forwarder is reachable; simply adding records without removing an unreachable forwarder will not fix forward lookups. Always check both forward and reverse resolution requirements.

Why the other options are wrong

B

The forwarder is unreachable, so keeping it will cause forward lookups to fail. Also, reverse lookup requires a PTR record, which is missing.

C

Forward lookups require an A record mapping the hostname to an IP address; without it, forward queries return NXDOMAIN.

D

The scenario expects R1 to be a local DNS server for internal hosts; using an external forwarder for internal hostnames is not best practice and may not resolve internal names if the forwarder doesn't have the records.

Why candidates pick the wrong answer

B

Candidates may think that adding an A record alone is sufficient and that the forwarder can be kept for other queries, not realizing the forwarder is unreachable.

C

Candidates may focus only on the reverse lookup issue mentioned in the problem and forget that forward lookups also fail due to the unreachable forwarder.

D

Candidates may think that using a public DNS server like 8.8.8.8 is a quick fix for forward lookups, but they overlook the requirement for local resolution and reverse lookup.

1306
Multi-Selectmedium

A branch router is acting as a DHCP server. Which two parameters can it provide directly to clients through DHCP?

Select 2 answers
A.Default gateway
B.DNS server address
C.OSPF area number
D.Switch port duplex setting
E.STP root bridge priority
AnswersA, B

DHCP Option 3 (Router) is used by clients to reach subnets beyond their local segment. When a branch router acts as a DHCP server, it must advertise a default gateway—typically its own LAN interface address—so endpoints can send off-subnet traffic. Without this parameter, clients can only communicate within the local broadcast domain.

Why this answer

DHCP (Dynamic Host Configuration Protocol) is designed to automatically assign IP configuration parameters to clients. The default gateway (option 3) and DNS server address (option 6) are standard DHCP options defined in RFC 2132, which a router acting as a DHCP server can directly provide to clients to enable network connectivity and name resolution.

Exam trap

Cisco often tests the distinction between DHCP-provided parameters (Layer 3/4) and switch-specific or routing protocol parameters (Layer 2/3), leading candidates to mistakenly select options like OSPF area or STP priority that are not DHCP options.

Why the other options are wrong

C

DHCP provides IP configuration parameters like default gateway and DNS server, not routing protocol parameters. OSPF area number is a routing protocol setting configured manually on routers, not assigned via DHCP.

D

DHCP provides IP configuration parameters like default gateway and DNS server, not physical layer settings like switch port duplex. Duplex is configured locally on the switch interface, not assigned via DHCP.

E

STP root bridge priority is a Spanning Tree Protocol parameter used to elect the root bridge in a switched network, not a DHCP-provided parameter. DHCP can only supply IP configuration parameters like default gateway and DNS server.

When would these options actually be correct?

C

In a question about OSPF configuration on a router, where you need to specify the area number for an interface under the OSPF process, e.g., 'network 192.168.1.0 0.0.0.255 area 0'.

D

In a question about switch port configuration, such as 'Which parameter is configured on a switch interface to match the connected device's capabilities?', switch port duplex setting would be correct.

E

In a question asking 'Which parameter is used in STP to determine the root bridge?', STP root bridge priority would be the correct answer, as it influences the root bridge election process.

Why candidates pick the wrong answer

C

Candidates may confuse DHCP options with network configuration parameters, thinking DHCP can assign any network-related setting, including routing protocol details.

D

Candidates may confuse DHCP's ability to provide network-layer parameters with physical-layer settings, or think DHCP can configure any device setting remotely.

E

Candidates may confuse DHCP with other network services or protocols, mistakenly thinking DHCP can provide Layer 2 or routing protocol parameters, especially when studying multiple topics simultaneously.

1307
MCQhard

An administrator needs to configure an ACL to block HTTP traffic from subnet 10.10.10.0/24 to the web server at 172.16.1.10 while permitting all other traffic. Which ACL entry should be placed first?

A.deny tcp 10.10.10.0 0.0.0.255 host 172.16.1.10 eq 80
B.deny ip 10.10.10.0 0.0.0.255 host 172.16.1.10
C.permit tcp 10.10.10.0 0.0.0.255 host 172.16.1.10 eq 80
D.deny udp 10.10.10.0 0.0.0.255 host 172.16.1.10 eq 80
AnswerA

This ACE must be listed first because ACLs are evaluated top-down, and this entry precisely matches TCP segments destined to port 80 from the 10.10.10.0/24 subnet to host 172.16.1.10. By specifying both the protocol (TCP) and the destination port (80), it denies only HTTP traffic to that server while leaving all other IP traffic, such as HTTPS or SSH, untouched and available for subsequent permit statements.

Why this answer

The ACL needs a narrow deny statement that matches only TCP port 80 from the specified source subnet to the specific server. In practical terms, the requirement is not to block all IP traffic or all access to the host. It is to stop normal HTTP while allowing everything else. That means the entry must be precise.

This is the kind of ACL question the CCNA exam likes because it forces you to distinguish protocol, destination, and service rather than relying on vague source-only logic.

Exam trap

Be careful to distinguish between blocking all traffic and blocking specific services. Ensure you understand the requirement to block only HTTP traffic, not all IP traffic.

Why the other options are wrong

B

Option B is incorrect because it denies all IP traffic from the specified source to the destination, which is broader than required and does not specifically target HTTP traffic on port 80.

C

Option C is incorrect because it permits HTTP traffic from the specified source to the web server, which is contrary to the requirement to block this traffic. The question specifically asks for a rule that denies HTTP access.

D

Option D is incorrect because it specifies 'deny udp', which does not block HTTP traffic, as HTTP uses TCP, not UDP. Therefore, it fails to meet the requirement of blocking HTTP from the specified source to the web server.

When would these options actually be correct?

B

If the exam question asked for a rule to block all traffic from 10.10.10.0/24 to the web server at 172.16.1.10, regardless of the protocol, then option B would be the correct answer as it effectively blocks all IP traffic.

C

In a different scenario where the question asks for an ACL entry to allow HTTP traffic from a specific subnet to a web server while blocking all other traffic, option C would be correct. For example, if the question stated to permit only HTTP traffic from 10.10.10.0/24 to 172.16.1.10, option C would fit.

D

In a different scenario where the question asks to block UDP traffic specifically from 10.10.10.0/24 to a service running on port 80 of the web server, option D would be the correct choice. For example, if the web server was configured to use a UDP-based protocol on port 80, this entry would be valid.

Why candidates pick the wrong answer

B

Candidates may choose this option because it appears to address the requirement of blocking traffic, but they overlook that it does not specify the HTTP protocol, leading to a broader and unintended denial of service.

C

Candidates may choose this option because it includes the correct source and destination addresses and specifies the correct protocol (TCP) and port (80), leading them to mistakenly believe it aligns with the intent of the question.

D

Candidates might choose this option due to a misunderstanding of the protocols involved, confusing HTTP (TCP) with potential UDP traffic, or they may incorrectly assume that blocking any traffic to the web server is sufficient.

1308
MCQhard

An administrator wants to prevent a specific subnet from using Telnet to reach network devices, while still allowing SSH from that same subnet. What is the strongest reason a standard ACL is not enough by itself?

A.Because the policy must distinguish Telnet from SSH, which requires protocol or port-level matching.
B.Because standard ACLs are valid only on wireless networks.
C.Because Telnet and SSH always use the same destination port.
D.Because SSH can never be filtered with ACLs.
AnswerA

This is correct because source-only matching cannot separate those two protocols.

Why this answer

A standard ACL is not enough by itself because the policy depends on distinguishing different protocols or destination ports, not just source address. In practical terms, the source subnet is the same for both Telnet and SSH. The ACL therefore needs to tell those two management protocols apart, which requires more granular matching than source-only logic.

This is one of the clearest examples of why extended ACL capability matters.

Exam trap

Do not confuse the capabilities of standard ACLs with those of extended ACLs. Remember, standard ACLs filter only by source IP.

Why the other options are wrong

B

Standard ACLs are not limited to wireless networks; they can be applied to any interface on a router, including wired connections. This option misrepresents the applicability of standard ACLs.

C

This option is incorrect because Telnet and SSH use different destination ports; Telnet typically uses port 23, while SSH uses port 22, allowing for distinct filtering in ACLs.

D

This option is incorrect because SSH can indeed be filtered using ACLs, as they can match traffic based on IP addresses and protocols. Standard ACLs can be applied to control SSH traffic just like any other traffic type.

When would these options actually be correct?

B

If a question stated that standard ACLs are only applicable to wireless networks and asked about their limitations in that context, then this option would be correct. For example, a scenario where a candidate must choose the best ACL type for a wireless-only environment would validate this statement.

C

If a question stated that both Telnet and SSH were configured to use the same port due to a specific network policy or misconfiguration, then this option could be correct, as it would imply that distinguishing between them would be impossible.

D

In a different exam scenario, if the question stated that SSH traffic is inherently unfilterable due to its encryption or that it operates on a unique protocol not recognized by ACLs, then this option could be correct. For example, a question could ask about filtering protocols that are not supported by ACLs.

Why candidates pick the wrong answer

B

Candidates may confuse the specific use cases of ACLs with network types, leading them to believe that standard ACLs have restrictions based on the type of network, rather than understanding their broader applicability.

C

Candidates might choose this option due to a misunderstanding of port assignments and the assumption that both protocols operate on the same layer, leading to confusion about their distinct characteristics.

D

Candidates may choose this option due to a misunderstanding of ACL capabilities, believing that the complexity of SSH encryption prevents any form of filtering, thus making it seem like a plausible answer.

1309
Multi-Selectmedium

Which three statements about Power over Ethernet (PoE) and PoE+ standards are correct? (Choose three.)

Select 3 answers
.PoE (IEEE 802.3af) can deliver up to 15.4 watts of power per port.
.PoE+ (IEEE 802.3at) can deliver up to 30 watts of power per port.
.Both PoE and PoE+ use the same four pairs of a twisted-pair cable for power delivery.
.Powered devices (PDs) can negotiate power requirements using Link Layer Discovery Protocol (LLDP) with PoE extensions.
.PoE+ requires Category 3 cabling or better.
.PoE automatically disables power if a non-PoE device is detected.

Why this answer

Option 1 is correct because the IEEE 802.3af PoE standard specifies a maximum power delivery of 15.4 watts per port at the PSE (Power Sourcing Equipment), with a minimum of 12.95 watts guaranteed at the PD (Powered Device) after cable losses. Option 2 is correct because the IEEE 802.3at PoE+ standard increases the maximum power per port to 30 watts at the PSE, with 25.5 watts available at the PD. Option 4 is correct because PDs can negotiate power requirements using LLDP with the IEEE 802.1AB LLDP-MED (Media Endpoint Discovery) extensions, which include PoE TLV (Type-Length-Value) fields for power negotiation beyond the simple classification method.

Option 3 (both PoE and PoE+ use the same four pairs) is incorrect because both standards deliver power over only two pairs (spare or data pairs depending on mode); four-pair power delivery is introduced in IEEE 802.3bt (PoE++). Option 5 (PoE+ requires Category 3 cabling) is incorrect because PoE+ requires at least Category 5e cabling to support the higher power levels without excessive heat or signal degradation. Option 6 (PoE automatically disables power if a non-PoE device is detected) is incorrect because the PSE first performs a detection phase to identify a valid PoE signature; if none is found, power is never applied—so it is not disabled after being enabled.

Exam trap

Cisco often tests the misconception that PoE and PoE+ both use all four pairs for power delivery, when in fact they use only two pairs, and the four-pair delivery is exclusive to the 802.3bt standard (PoE++).

Why the other options are wrong

C

Both PoE and PoE+ use only two pairs for power delivery, not four; four-pair delivery is exclusive to 802.3bt (PoE++).

E

PoE+ requires Category 5e or better cabling, as Category 3 cannot safely support the higher current.

F

PoE does not disable power on a non-PoE device; detection prevents power from ever being applied to non-compliant devices.

1310
MCQhard

Which NAT design is most appropriate when many inside users need outbound Internet access through one public IPv4 address, but no inbound server publishing is required?

A.PAT overload
B.Static NAT for every host
C.No NAT, because private IPv4 addresses are Internet-routable
D.DHCP relay
AnswerA

PAT overload (Port Address Translation) is the correct choice because it allows many internal devices to share a single public IPv4 address by multiplexing sessions based on transport-layer port numbers. Each inside host's traffic is assigned a unique source port, enabling thousands of concurrent outbound connections from a single public IP. This conserves the limited public IPv4 address space and is the standard solution for providing Internet access to a large user population.

Why this answer

The most appropriate design is PAT overload. In practical terms, many internal users can share one public IPv4 address because PAT distinguishes their sessions using transport-layer ports. This is the most common solution when the requirement is outbound access for many clients rather than predictable inbound access to a specific internal server.

Static NAT would be the wrong design here because it creates fixed one-to-one mappings and consumes more public address space than needed for this use case. PAT is specifically built for many-to-one outbound translation.

Exam trap

A frequent exam trap is selecting static NAT or no NAT for outbound Internet access when many internal users share one public IP. Static NAT creates one-to-one mappings, consuming excessive public IP addresses unnecessarily. Choosing no NAT assumes private IPv4 addresses are routable on the Internet, which is false.

Another trap is confusing DHCP relay with NAT; DHCP relay only forwards DHCP messages and does not perform address translation. Candidates must recognize that PAT overload is the correct design for many-to-one outbound translation without inbound server publishing, avoiding these common misconceptions.

Why the other options are wrong

B

Static NAT for every host is incorrect because it requires a unique public IP address per internal host, which is inefficient and unnecessary when only outbound access is needed without inbound server publishing.

C

No NAT is incorrect because private IPv4 addresses are not routable on the public Internet and must be translated to public addresses to communicate externally.

D

DHCP relay is incorrect because it only forwards DHCP messages between clients and servers and does not perform any IP address translation or NAT functions.

When would these options actually be correct?

B

In a scenario where a network requires consistent inbound access to specific services hosted on internal servers, such as a web server or mail server, using Static NAT for those specific hosts would be appropriate to ensure that they are always reachable via the same public IP address.

C

If the exam question stated that the network was using a new protocol or technology that allows private IPv4 addresses to be routable on the Internet, then 'No NAT' could be a correct answer. For example, if the question involved a scenario where IPv6 was implemented, making private IPv4 addresses routable would be valid.

D

If the question asked about a scenario where a network has multiple subnets and requires dynamic IP address assignment from a remote DHCP server, then DHCP relay would be the correct answer. This would involve forwarding DHCP packets across different network segments.

Why candidates pick the wrong answer

B

Candidates might choose this option because they recall that Static NAT provides a direct mapping between private and public IPs, which can seem appealing for ensuring reliable communication, even though it doesn't fit the question's requirements.

C

Candidates may choose this option due to a misunderstanding of NAT concepts, believing that private addresses can be used directly on the Internet without realizing the necessity of NAT for outbound connectivity.

D

Candidates may confuse DHCP relay with NAT functions, thinking that it relates to managing IP addresses for Internet access, leading them to select it despite it not addressing the specific requirements of the question.

1311
MCQmedium

Exhibit: Users complain of slow wireless performance in a dense office even though signal strength is strong. Multiple APs are using channels 1, 2, and 3 on 2.4 GHz. Which change is most appropriate?

A.Reduce all AP transmit power to zero
B.Move to non-overlapping channels such as 1, 6, and 11
C.Change every AP to the same channel for consistency
D.Disable WPA2 security
AnswerB

In the 2.4 GHz ISM band, adjacent channel interference is unavoidable if channels are spaced closer than 25 MHz, so planning APs on the three non-overlapping channels 1, 6, and 11 ensures that overlapping coverage cells do not transmit on the same or partially overlapping frequencies. This eliminates co-channel and adjacent-channel contention, allowing the CSMA/CA medium access protocol to work efficiently and restoring throughput for users.

Why this answer

In 2.4 GHz, overlapping channels cause co-channel and adjacent-channel interference. The common non-overlapping choices are 1, 6, and 11. Moving away from overlapping channels usually improves performance in a dense deployment.

Exam trap

Avoid assuming that increasing power or adding more APs will solve interference issues without considering channel overlap.

Why the other options are wrong

A

Reducing all AP transmit power to zero would completely disable the wireless network, making it impossible for users to connect or experience any performance, which does not address the issue of slow performance in a dense office environment.

C

Changing every AP to the same channel would lead to co-channel interference, exacerbating the slow wireless performance issue rather than resolving it. In a dense office environment, this configuration would reduce overall throughput and increase contention among devices.

D

Disabling WPA2 security would not address the issue of slow wireless performance in a dense office environment; instead, it would compromise network security and potentially allow unauthorized access, worsening the situation.

When would these options actually be correct?

A

In a scenario where an exam question asks about troubleshooting a wireless network that is experiencing interference and requires a drastic reduction in signal strength to mitigate overlapping signals, setting AP transmit power to zero could be a valid solution to eliminate interference.

C

In a different scenario where a question asks about simplifying network management in a small, isolated environment with minimal interference, setting all APs to the same channel could be beneficial. This would ensure consistent performance and easier troubleshooting in a low-density setting.

D

In a different scenario where the question focuses on a network that is experiencing connectivity issues due to excessive security protocols, disabling WPA2 could be a correct answer. For example, if the question states that users are unable to connect to the network due to WPA2 misconfigurations, then disabling it temporarily for troubleshooting could be appropriate.

Why candidates pick the wrong answer

A

Candidates may mistakenly believe that reducing transmit power will alleviate congestion and improve performance in a dense environment, not recognizing that it would instead eliminate connectivity altogether.

C

Candidates may be tempted by the idea that uniformity in channel assignment could simplify network management and reduce complexity, leading them to overlook the potential for increased interference in a dense environment.

D

Candidates may choose this option due to a misunderstanding of the relationship between security settings and performance, mistakenly believing that reducing security might improve connectivity in congested environments.

1312
Drag & Dropmedium

Drag and drop the following steps into the correct order to configure HSRP on an interface and verify the active/standby election process, including failover and verification.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

Only option A correctly orders the steps for configuring HSRP on an interface. The proper sequence is: enter interface configuration mode, set the HSRP version, configure the virtual IP, set priority if needed, enable preempt, and verify with 'show standby'. Options B, C, and D contain incorrect steps or order.

B suggests creating a VLAN and assigning an IP to the VLAN interface, which is not part of HSRP configuration (HSRP is configured on an existing Layer 3 interface, not by creating a VLAN). C places priority before virtual IP and uses 'show running-config' for verification, which does not show active/standby roles. D incorrectly assumes HSRP is enabled globally and uses 'debug standby' for initial verification, which is not the standard first verification command.

Exam trap

Candidates often confuse the order of HSRP configuration steps or think HSRP requires a global configuration mode like routing protocols. Remember: HSRP is configured per interface, and verification uses 'show standby' to see real-time roles.

Why candidates pick the wrong answer

B

Candidates may confuse HSRP with VLAN configuration or think HSRP requires a separate VLAN step.

C

Candidates might think priority is the most important parameter and set it first, or confuse verification commands.

D

Candidates may be familiar with routing protocols that have a global process (e.g., 'router eigrp') and assume HSRP works similarly.

1313
MCQhard

A switch shows a clock that is several minutes off from other devices even though an NTP server has been configured. Which issue is the most likely cause?

A.The NTP server is unsynchronized or unreachable
B.The device must run Syslog before NTP can sync
C.NTP requires a trunk port on the management VLAN
D.The clock can sync only if DNS is configured
AnswerA

NTP clients trust time only from a server that is both reachable and itself synchronized to a reference clock. When the server is unreachable (e.g., UDP 123 is filtered) or its stratum is too high because it lost its upstream source, the switch discards the NTP packets and retains the local clock, which drifts after several minutes. The remedy is to verify the server's stratum and reachability before adjusting anything else.

Why this answer

NTP requires IP reachability to the time source. If the NTP server is unreachable due to routing or ACL issues, the switch falls back to its local clock, causing drift. Option A is correct.

Option B is wrong because Syslog has no effect on NTP synchronization. Option C is incorrect because NTP does not require a trunk port; it can operate over any VLAN with IP connectivity. Option D is false because DNS is only needed if the NTP server is specified by hostname; the server can be reached by IP address without DNS.

Exam trap

A common mistake is thinking that unrelated services like Syslog, trunk ports, or DNS are prerequisites for NTP; only IP connectivity to a synchronized NTP server matters.

Why the other options are wrong

B

Syslog and NTP are independent protocols; Syslog does not need to run before NTP can synchronize.

C

NTP works over any IP network; there is no requirement for a trunk port on the management VLAN.

D

DNS is only needed if the NTP server is referenced by hostname rather than IP address; many configurations use IP addresses directly.

When would these options actually be correct?

B

In a different question scenario where a device is configured to log events via Syslog, and the exam asks about prerequisites for time synchronization, this option could be correct if the question indicated that Syslog must be operational for NTP to function correctly in that specific context.

C

In a different exam scenario where the question specifies that NTP traffic must traverse a trunk port due to VLAN segmentation, and the switch is misconfigured to not allow NTP on that trunk, this option could be correct.

D

In a different scenario where a question states that a device is unable to resolve the NTP server's hostname due to DNS misconfiguration, option D would be correct. This would imply that the device cannot reach the NTP server at all, thus failing to sync its clock.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of the relationship between logging and time synchronization, believing that logging services must be active for NTP to function properly, reflecting a common misconception in network management.

C

Candidates may choose this option due to a misunderstanding of VLAN configurations and their impact on network services, leading them to incorrectly associate trunk ports with NTP functionality.

D

Candidates might choose this option due to a misunderstanding of how NTP operates, believing that hostname resolution is a prerequisite for synchronization, especially if they have encountered scenarios where DNS issues affected other services.

1314
MCQmedium

Users on a new access switch can reach devices in their own VLAN but cannot reach the default gateway on the distribution switch. Based on the exhibit, what is the most likely cause?

A.VLAN 30 is missing from the allowed VLAN list on the trunk.
B.The user ports should be configured as trunks.
C.The SVI for VLAN 30 must be shutdown for inter-VLAN routing to work.
D.The trunk native VLAN must be changed to VLAN 30.
AnswerA

On a trunk, a VLAN must be present in the allowed VLAN list for its frames to traverse the link. If VLAN 30 was not explicitly added to the allowed list, frames from that VLAN are dropped at the trunk port, so they never reach the distribution switch. This prevents inter-VLAN routing even though local hosts within VLAN 30 on the access switch can communicate. Adding 'allowed vlan add 30' to the trunk configuration restores connectivity.

Why this answer

The trunk allows only VLANs 10 and 20, so VLAN 30 traffic never crosses the uplink. Local switching inside VLAN 30 on the access switch can still work, which is why same-VLAN communication succeeds. Adding VLAN 30 to the allowed list is the direct fix.

Exam trap

A common exam trap is assuming that user ports must be trunks to enable VLAN communication beyond the local switch. In reality, user ports should remain access ports assigned to a single VLAN. Another trap is thinking that the SVI for VLAN 30 must be shut down to fix routing issues, but an active SVI is necessary for inter-VLAN routing.

Additionally, candidates may incorrectly focus on native VLAN mismatches, which do not block VLAN 30 traffic if the VLAN is not allowed on the trunk. The real issue is the missing VLAN 30 in the trunk's allowed VLAN list, which prevents VLAN 30 frames from reaching the distribution switch and the default gateway.

Why the other options are wrong

B

Incorrect because user ports should be configured as access ports, not trunks. Configuring user ports as trunks is unnecessary and can cause security and connectivity issues.

C

Incorrect because the SVI for VLAN 30 must be active for inter-VLAN routing to function. Shutting down the SVI would prevent routing, not enable it.

D

Incorrect because changing the trunk native VLAN to VLAN 30 is unrelated to the problem. Native VLAN mismatches affect untagged traffic but do not block VLAN 30 tagged frames if the VLAN is allowed.

When would these options actually be correct?

B

In a different scenario where users need to connect multiple VLANs on a single port, such as in a network with multiple VLANs on a single access switch, configuring user ports as trunks would be necessary to allow traffic from multiple VLANs to traverse the same port.

C

In a scenario where the question states that VLAN 30 is configured but the SVI for VLAN 30 is administratively down, the option would be correct. This would indicate that users in VLAN 30 cannot route traffic to the default gateway because the SVI is not active.

D

In a different scenario where the question states that users are unable to communicate with devices in other VLANs due to misconfigured native VLAN settings, changing the trunk native VLAN to VLAN 30 could resolve issues with untagged traffic being misrouted.

Why candidates pick the wrong answer

B

Candidates may confuse the need for VLAN communication with the concept of trunking, mistakenly believing that user ports should be set as trunks to facilitate access to the default gateway.

C

Candidates may choose this option because they understand the importance of SVIs in routing and might mistakenly believe that a shutdown SVI would directly impact connectivity to the default gateway for devices in the same VLAN.

D

Candidates may find this option tempting because they might confuse native VLAN settings with VLAN communication issues, thinking that adjusting the native VLAN could resolve routing problems between VLANs.

1315
MCQhard

A network engineer notices that the router interface GigabitEthernet0/1 is in an 'administratively down' state in the output of the show ip interface brief command, preventing connectivity to the subnet connected to that interface. What is the most likely cause?

A.The interface does not have an IP address assigned.
B.The shutdown command is configured on the interface.
C.The interface is configured with an incorrect subnet mask.
D.An access list is blocking traffic on the interface.
AnswerB

The 'administratively down' status is only displayed when the interface has been explicitly disabled using the shutdown command in configuration mode. This command sets a software flag that prevents the interface from forwarding any traffic and forces the line status to 'administratively down' regardless of the physical connection. It is a direct, intentional administrative action, and the interface will remain in this state until the no shutdown command is issued. Thus, the shutdown command is the definitive cause for this status.

Why this answer

The 'administratively down' state in the output of 'show ip interface brief' indicates that the interface has been manually disabled using the 'shutdown' command. This is a Layer 1/2 administrative state, not a protocol or connectivity issue. To bring the interface up, the 'no shutdown' command must be applied in interface configuration mode.

Exam trap

Cisco often tests the distinction between 'administratively down' (caused by the 'shutdown' command) and 'down/down' (caused by a physical layer issue like a disconnected cable), leading candidates to confuse the two states.

Why the other options are wrong

A

Candidates often confuse the lack of an IP address with a non-functional interface, believing it will be shown as down.

C

Students may think any IP misconfiguration could bring the interface down, but only the shutdown command causes 'administratively down'.

D

Because an ACL can stop traffic, candidates sometimes assume it would be reflected as a down state, but interface status is independent of ACLs.

1316
Drag & Dropmedium

Drag and drop the following OSPFv2 neighbor state transitions and DR/BDR election steps into the correct order for a multi-access network where a new router joins an existing OSPF area.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

The new router first discovers neighbors via Hello. Then DD, LSR, LSU exchange synchronizes databases. DR/BDR election happens before Full state is achieved.

Exam trap

Do not confuse the order of ExStart and Exchange, or Loading and Full. Remember that DR/BDR election occurs after 2-Way and before ExStart.

Why candidates pick the wrong answer

B

Candidates might confuse the order of Loading and Full, thinking Full is reached earlier.

C

Candidates might think that ExStart (negotiation) happens immediately after Init, skipping the 2-Way confirmation.

D

Candidates might mistakenly think that database exchange (Exchange) starts immediately after 2-Way, forgetting the negotiation step.

1317
MCQhard

An engineer wants remote administrative access to remain available but also wants session contents protected in transit. Which management choice best supports that goal?

A.SSH
B.Telnet
C.Open wireless access
D.Native VLAN 1
AnswerA

SSH (Secure Shell) is the correct choice because it provisions an encrypted tunnel for remote administrative sessions, typically on TCP port 22. It validates the server's identity via host keys, encrypts all authentication material and subsequent command output, and provides integrity checking. This protects credentials and configuration changes from being observed or tampered with en route, making it the only listed option that offers secure remote administration.

Why this answer

The best choice is SSH because it provides encrypted remote administrative access. In plain language, the engineer wants administrators to keep managing devices remotely, but without exposing credentials or session contents in clear text. SSH solves that by protecting the traffic in transit, which is why it is preferred over older plaintext protocols such as Telnet.

This is a core management-plane security principle. The goal is not to remove remote administration, but to perform it safely. The correct answer is the one that aligns with secure remote access rather than convenience at the expense of protection.

Exam trap

A common exam trap is selecting Telnet because it allows remote access, ignoring that it transmits data in clear text. This mistake overlooks the critical security requirement to protect session contents during transit. Another trap is choosing options unrelated to encryption, such as native VLAN or open wireless access, which do not address secure remote management.

Candidates must focus on protocols that provide confidentiality and integrity for administrative sessions, not just connectivity.

Why the other options are wrong

B

Telnet is incorrect because it transmits data in clear text, exposing sensitive information to attackers and failing to protect session contents during transit.

C

Open wireless access is unrelated to secure remote management; it does not provide encryption or protect administrative sessions, making it irrelevant to the question.

D

Native VLAN 1 configuration does not affect encryption or security of remote management protocols, so it does not support the goal of protecting session contents.

When would these options actually be correct?

B

If the exam question asked for a method of remote access that prioritizes speed and simplicity over security, and the context was a controlled environment where security risks are minimal, Telnet could be considered acceptable.

C

If the question were about providing remote access to a public network where encryption is not a concern, and the focus was solely on ease of access rather than security, then open wireless access could be considered a valid option.

D

If the question asked about configuring a network switch for management access without any security requirements, or if it specifically focused on VLAN configurations for untagged traffic, then selecting Native VLAN 1 could be correct.

Why candidates pick the wrong answer

B

Candidates may choose Telnet due to its historical use in networking and familiarity, mistakenly believing that it is still a viable option for remote access without recognizing the security implications.

C

Candidates may choose this option due to a misunderstanding of wireless security, believing that open access is sufficient for remote management without recognizing the risks of unencrypted data transmission.

D

Candidates may be tempted by this option because they recognize VLANs as a fundamental networking concept and might mistakenly associate Native VLAN 1 with management access without considering the security implications.

1318
MCQmedium

A network engineer enters the following configuration on R1 and R2, but R1 cannot form an OSPF adjacency with R2 on interface GigabitEthernet0/0. R1# show running-config interface GigabitEthernet0/0 interface GigabitEthernet0/0 ip address 10.0.0.1 255.255.255.0 ip ospf hello-interval 10 ip ospf dead-interval 40 ip ospf 1 area 0 ! R2# show running-config interface GigabitEthernet0/0 interface GigabitEthernet0/0 ip address 10.0.0.2 255.255.255.0 ip ospf hello-interval 5 ip ospf dead-interval 20 ip ospf 1 area 0 What is the most likely cause of the failure?

A.The routers are in different OSPF areas.
B.The OSPF timers on the interface do not match.
C.The subnet mask prevents multicast OSPF packets from being exchanged.
D.The OSPF process IDs do not match on the two routers.
AnswerB

This is correct because the interfaces are configured with different hello and dead intervals. OSPF neighbors expect those timers to align, and if they do not, the routers reject the neighbor relationship. The addressing and area assignment are fine, but the timer mismatch blocks adjacency formation.

Why this answer

The routers must agree on hello and dead timers to establish an OSPF adjacency. R1 uses hello=10 and dead=40, while R2 uses hello=5 and dead=20; this mismatch prevents the neighbor relationship. Although both routers share the same area (0) and subnet mask, and OSPF process IDs are locally significant (no match required), the timer difference is the root cause.

Exam trap

Remember that OSPF process IDs are locally significant and do not need to match between routers.

Why the other options are wrong

A

This option is incorrect because OSPF can still form adjacencies between routers in different areas, provided they are correctly configured to do so. The issue in this scenario is related to OSPF timers, not area mismatches.

C

This option is incorrect because OSPF can still exchange multicast packets even if the subnet mask is not configured correctly, as long as the interfaces are up and configured for OSPF. The failure to form an adjacency is more likely due to mismatched OSPF timers.

D

This option is wrong because OSPF process IDs do not need to match for routers to form an adjacency; they only need to be in the same area and have matching network statements.

When would these options actually be correct?

A

In a different exam scenario, if the question specified that both routers were configured in the same OSPF area but were unable to establish an adjacency due to misconfiguration, then this option would be correct. For example, if both routers were in area 0 but had different area types, this could prevent adjacency formation.

C

In a different scenario, if the question specified that the routers are on the same subnet but the subnet mask is incorrectly configured, preventing the multicast OSPF packets from being sent or received, then this option would be correct. For example, if R1 has a subnet mask of 255.255.255.0 and R2 has 255.255.0.0, they would not be able to communicate properly.

D

In a different scenario, if the question stated that R1 and R2 were configured to use different OSPF process IDs and were in the same area, this option would be correct, as OSPF requires matching process IDs for adjacency formation.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a common misconception that OSPF adjacency can only be formed within the same area, leading them to overlook other potential issues like timer mismatches.

C

Candidates might choose this option because they understand that OSPF relies on multicast communication, and they may incorrectly assume that any subnet mask issue would directly prevent OSPF adjacency, without considering the specific context of the question.

D

Candidates may choose this option due to a common misconception that OSPF process IDs are critical for adjacency, leading them to overlook other more relevant factors like area configuration or timer settings.

1319
MCQhard

Why is HTTPS preferred over HTTP when accessing sensitive controller APIs?

A.Because HTTPS encrypts the API traffic in transit.
B.Because HTTPS removes the need for tokens and credentials.
C.Because HTTPS is the only way JSON can be transmitted.
D.Because HTTP cannot carry API requests at all.
AnswerA

HTTPS wraps the API payload in TLS/SSL encryption, so any sensitive data transmitted over the network—such as passwords, tokens, or personal information—remains unreadable to anyone who intercepts the packets. This prevents eavesdropping and man-in-the-middle attacks, which is why secure communication is mandatory for sensitive operations. In contrast, HTTP sends all data as plaintext, leaving it exposed on shared networks.

Why this answer

HTTPS is preferred because it encrypts the traffic in transit. In practical terms, sensitive controller APIs may carry tokens, credentials, operational details, and configuration data. Sending that information over plain HTTP would expose it to interception on the network. HTTPS reduces that risk by protecting the session.

This does not make HTTPS a replacement for authentication. It is a transport-security choice that works alongside access control, not instead of it.

Exam trap

A frequent exam trap is believing that HTTPS removes the need for tokens or credentials in API access. Some candidates incorrectly assume that because HTTPS encrypts traffic, authentication is unnecessary. However, HTTPS only secures the transport layer and does not provide access control.

Another trap is thinking HTTP cannot carry API requests, which is false since HTTP can transmit API data but without encryption. Also, confusing the data format with the transport protocol leads to the incorrect belief that JSON requires HTTPS, when in fact JSON can be sent over any protocol. Understanding these distinctions is crucial to avoid selecting incorrect answers.

Why the other options are wrong

B

Option B is incorrect because HTTPS does not remove the need for tokens or credentials; it only secures the transport layer. Authentication is still required to control access to APIs.

C

Option C is incorrect since JSON can be transmitted over any protocol, including HTTP and HTTPS. The choice of HTTPS is about securing the transport, not the data format.

D

Option D is incorrect because HTTP can carry API requests; however, it does so without encryption, making it unsuitable for sensitive data transmission.

When would these options actually be correct?

B

In a different question that asks about the advantages of HTTPS in a context where security measures are being discussed, and specifically mentions that HTTPS can eliminate the need for certain types of insecure credentials, this option could be correct. For example, if the question stated that HTTPS allows for secure session management without exposing tokens.

C

In a different exam scenario, if the question specifically stated that JSON can only be transmitted securely, or if it asked about protocols that support JSON exclusively, then this option could be correct. For example, a question could ask, 'Which protocol is exclusively used for transmitting JSON data?'

D

In a question that specifically asks about the capabilities of HTTP versus other protocols, such as when comparing HTTP to a protocol that does not support API requests at all, this option could be correct. For example, if the question stated, 'Which protocol cannot handle API requests?' then D would be the correct answer.

Why candidates pick the wrong answer

B

Candidates may find this option tempting because they might confuse the security features of HTTPS with the overall simplification of authentication processes, leading them to believe that HTTPS inherently negates the need for any credentials.

C

Candidates may choose this option due to a misunderstanding of how protocols work and the assumption that security protocols inherently dictate data formats, leading them to conflate HTTPS with specific data types.

D

Candidates may choose this option due to a misunderstanding of HTTP's capabilities, possibly influenced by discussions about security where HTTPS is emphasized over HTTP, leading to the false assumption that HTTP is entirely ineffective for APIs.

1320
MCQhard

An API response returns a list of interface objects in JSON. Which structure most likely represents that list?

A.An array containing multiple interface objects
B.A single integer with the value 1
C.A native VLAN field
D.An STP root bridge ID
AnswerA

An array containing multiple interface objects is the correct representation because JSON arrays are explicitly designed to hold an ordered collection of repeated items, with each element separated by a comma and enclosed in square brackets. In a REST API response, a list of interfaces is naturally modeled as an array where each element is a JSON object containing key-value pairs such as interface name, status, and IP address. This directly matches the request for a list of interface objects, making it the appropriate structure for the response.

Why this answer

In JSON, a list is most naturally represented as an array. In plain language, when an API needs to return several interfaces, routes, VLANs, or similar repeated items, it usually places them inside square brackets as an ordered collection. Each item inside that array might itself be an object containing keys such as name, status, or IP address.

CCNA automation questions usually test whether you recognize that square brackets signal a list. If the response contains many similar interface records, the best structure is the one that looks like a JSON array of interface objects rather than a single scalar value.

Exam trap

Remember that arrays in JSON are denoted by square brackets, and each item should be a complete object if details are needed.

Why the other options are wrong

B

Option B is incorrect because an API response that returns a list of interface objects should be structured as an array, not as a single integer. A single integer does not represent a collection of objects.

C

A native VLAN field is not a valid representation of a list of interface objects in JSON; it typically refers to a specific VLAN configuration in networking, not an array structure.

D

Option D is incorrect because an STP root bridge ID is a specific identifier related to Spanning Tree Protocol, not a representation of a list of interface objects in JSON format.

When would these options actually be correct?

B

If the exam question asked for the response of an API that simply returns a status code or a numeric value indicating success or failure, then a single integer could be the correct answer. For example, 'What does the API return when a request is successful?' could lead to this option being correct.

C

In a question asking for the representation of VLAN configurations in a network device's JSON output, where the native VLAN is being queried, this option could be correct if the question specifically asks for a single VLAN identifier.

D

In a different question that asks for the identification of a specific attribute within a JSON object related to network topology, such as 'What identifies the root bridge in a spanning tree configuration?', option D would be the correct answer.

Why candidates pick the wrong answer

B

Candidates may find this option tempting because they might confuse the concept of an API response with a simple status code or numeric indicator, which can sometimes be part of API interactions, leading to misinterpretation of the question's requirements.

C

Candidates may confuse the concept of VLANs with API responses, mistakenly thinking that VLAN-related fields could represent a list of interfaces, especially if they have encountered similar terms in networking contexts.

D

Candidates may choose this option due to familiarity with networking concepts, mistakenly believing that any network-related term could be relevant to JSON structures, leading to confusion between different data types.

1321
MCQhard

A subnet uses the prefix /29. How many usable host addresses are available in each subnet?

A.2
B.6
C.14
D.30
AnswerB

A /29 prefix leaves 3 host bits (32 - 29 = 3), yielding 2^3 = 8 total IPv4 addresses in the subnet. After reserving one address for the network identifier and one for the directed broadcast address, exactly 8 - 2 = 6 addresses remain assignable to hosts. This matches the formula 2^(32 - prefix) - 2, which is the standard way to calculate usable host capacity.

Why this answer

A /29 prefix leaves 3 host bits, which creates 8 total addresses per subnet. In plain language, two of those addresses cannot be assigned to hosts because one identifies the subnet itself and one is reserved as the broadcast address. That leaves 6 usable host addresses. This is a standard CCNA calculation because it checks whether you understand both the total address count and the subtraction of the reserved addresses.

Many candidates remember powers of two but forget to account for the network and broadcast addresses when the question asks for usable hosts. The safest process is to calculate the total size first and then reduce it by two. That is how you arrive at 6 usable addresses for a /29.

Exam trap

Remember to subtract the network and broadcast addresses from the total count to find usable addresses.

Why the other options are wrong

A

Option A is incorrect because a /29 subnet provides 8 total IP addresses, of which 6 are usable for hosts after accounting for the network and broadcast addresses.

C

Option C is wrong because a /29 subnet provides 8 total IP addresses, of which 6 are usable for hosts after reserving one for the network address and one for the broadcast address.

D

Option D is incorrect because a /29 subnet provides 8 total IP addresses, of which 6 are usable for hosts after accounting for the network and broadcast addresses. Therefore, stating that there are 30 usable addresses is inaccurate.

When would these options actually be correct?

A

In a hypothetical question asking for the number of usable addresses in a /30 subnet, option A would be correct, as a /30 subnet has 4 total addresses, resulting in 2 usable host addresses.

C

If the question specified a /28 subnet instead of /29, then option C would be correct, as a /28 subnet allows for 16 total IP addresses, resulting in 14 usable host addresses after accounting for the network and broadcast addresses.

D

In a different context, if the question asked about a subnet with a prefix of /26, which allows for 62 usable host addresses, option D could be correct. This would require candidates to calculate usable addresses based on a larger subnet size.

Why candidates pick the wrong answer

A

Candidates may choose this option due to confusion between the total number of addresses and the usable ones, or they might mistakenly associate /29 with a smaller subnet size like /30, leading to the miscalculation.

C

Candidates might choose option C due to a misunderstanding of subnetting, mistakenly calculating the usable addresses by only considering the total number of addresses without accounting for the reserved network and broadcast addresses.

D

Candidates may choose option D due to confusion between the total number of addresses and the usable ones, or they might mistakenly recall common subnet sizes that yield higher usable addresses, leading to an overestimation.

1322
MCQmedium

A network engineer needs to automate the configuration of multiple Cisco IOS XE routers in a data center. The team requires a standard, vendor-neutral data modeling language to define the configuration parameters, and they need a protocol that uses XML-based remote procedure calls over SSH for secure, reliable configuration transactions. Which combination of technologies best meets these requirements?

A.Use YANG data models combined with RESTCONF over HTTPS.
B.Use YANG data models combined with NETCONF over SSH.
C.Use CLI commands combined with NETCONF over SSH.
D.Use CLI commands combined with RESTCONF over HTTPS.
AnswerB

YANG plus NETCONF over SSH is the standard model-driven management combination: YANG provides a vendor-neutral, hierarchical data model for configuration and state data, while NETCONF carries those models in XML-encoded RPCs over an encrypted SSH session. The NETCONF session supports transactions across multiple configuration datastores (candidate, running, startup), giving reliable commit/rollback behavior. This pairing exactly matches the requirements for a standardized data model and secure, remote procedure-style configuration exchange.

Why this answer

YANG is a standard, vendor-neutral data modeling language (RFC 6020) for defining configuration parameters, and NETCONF (RFC 6241) uses XML-based remote procedure calls (RPCs) over SSH for secure, reliable configuration transactions. This combination directly satisfies the requirement for a standard data model and XML-based RPCs over SSH, unlike RESTCONF which uses HTTPS and JSON/XML but not SSH.

Exam trap

Cisco often tests the distinction between NETCONF (XML RPCs over SSH) and RESTCONF (RESTful operations over HTTPS), and candidates mistakenly choose RESTCONF because it is more modern, but the question explicitly requires XML-based RPCs over SSH, which only NETCONF provides.

Why the other options are wrong

A

The scenario specifies a protocol that uses XML-based RPCs over SSH, which is a characteristic of NETCONF, not RESTCONF.

C

The scenario specifically asks for a standard, vendor-neutral data modeling language, which CLI is not.

D

Neither the data modeling language (CLI) nor the protocol (RESTCONF) matches the specified requirements of vendor-neutral data modeling and XML-based RPCs over SSH.

1323
MCQhard

A network engineer notices that internal hosts (192.168.1.0/24) can reach external servers on the internet, but replies from external servers never reach the internal hosts. The router R1 is configured with dynamic NAT to translate the internal subnet to a pool of public IPs (203.0.113.10-203.0.113.20). The engineer runs 'show ip nat translations' and sees only a few stale translations. What is the most likely cause of the issue?

A.The access list 'NAT' is incorrect; it should permit only specific hosts, not the entire subnet.
B.The outside interface (GigabitEthernet0/0) is missing the 'ip nat outside' command.
C.The NAT configuration lacks the 'overload' keyword, so the pool is exhausted quickly.
D.The NAT pool 'POOL' has too few addresses; it should be expanded to a /24 subnet.
AnswerB

The outside interface GigabitEthernet0/0 is missing the 'ip nat outside' command, which breaks NAT in both directions. For NAT to function, each interface must be explicitly marked as either 'ip nat inside' or 'ip nat outside'. With only 'ip nat inside' on the internal interface and no 'ip nat outside' on the external interface, the router will translate the source IP of outgoing packets but will not know to translate the destination IP of incoming return packets. Therefore, the return traffic cannot be matched to the existing translation entry, and the response packets are dropped or sent without translation, causing the no-reply symptom.

Why this answer

The 'ip nat outside' command must be applied to the interface facing the external network (GigabitEthernet0/0) for the router to translate return traffic. Without it, the router does not perform NAT on packets arriving on that interface, so replies from external servers are forwarded without translation back to the inside local IPs, which are not routable on the internet. The stale translations indicate that outbound translations were created but never used for return traffic, confirming the missing outside interface command.

Exam trap

Cisco often tests the requirement that both 'ip nat inside' and 'ip nat outside' must be configured on the respective interfaces for NAT to work bidirectionally, and the trap here is that candidates assume only the inside interface needs the command or confuse the symptom with pool exhaustion or ACL issues.

Why the other options are wrong

A

The access list correctly matches the internal subnet, so this is not the root cause.

C

Even without overload, dynamic NAT should work for the first 11 hosts; the problem is that return packets are not being translated.

D

The pool size is not the issue; the router is not translating return traffic due to missing 'ip nat outside'.

1324
PBQhard

You are connected to a Cisco 9800 WLC (WLC1) via its management interface. A wireless client reports association failures with SSID 'CorpNet'. The client uses WPA3-Personal, but the WLAN is configured for WPA2. Additionally, the SSID is hidden and the client is on the wrong VLAN (VLAN 20 instead of VLAN 100). Fix these issues so the client can associate successfully with WPA3, on VLAN 100, and with the SSID broadcast enabled.

Network Topology
192.168.100.2/24networkWLC1AP

Hints

  • Check the WLAN security settings: WPA3 requires 'security wpa wpa3' and removal of 'wpa2'.
  • The SSID is hidden; use 'broadcast-ssid' under the WLAN configuration.
  • The policy tag assigns VLAN 20; change it to VLAN 100 to match client requirements.
A.Enable SSID broadcast, change security to WPA3-Personal, and assign VLAN 100 in the policy tag.
B.Enable SSID broadcast, change security to WPA2-PSK, and assign VLAN 20 in the policy tag.
C.Disable SSID broadcast, change security to WPA3-Personal, and assign VLAN 100 in the policy tag.
D.Enable SSID broadcast, change security to WPA3-Enterprise, and assign VLAN 100 in the policy tag.
AnswerA
solution
! WLC1
configure terminal
wlan CorpNet 1 CorpNet
broadcast-ssid
no security wpa wpa2
security wpa wpa3
security wpa psk set-ccmp 0 7 1234567890
exit
wireless tag policy default-policy
vlan 100
end
write memory

Why this answer

The WLAN was configured for WPA2-PSK with a hidden SSID, and the policy tag assigned VLAN 20 instead of VLAN 100. To fix: (1) Enable SSID broadcast with 'broadcast-ssid'. (2) Change security to WPA3-Personal by removing WPA2 and enabling WPA3 with 'security wpa wpa3' and 'security wpa psk set-ccmp'. (3) Assign VLAN 100 in the policy tag with 'vlan 100'. The client should then associate.

Exam trap

Be careful to distinguish between WPA2 and WPA3, and between Personal (PSK) and Enterprise (802.1X). Also, remember that a hidden SSID must be broadcast for clients to discover it, and VLAN assignment is done in the policy tag, not the SSID configuration.

Why the other options are wrong

B

The specific factual error is that the client uses WPA3-Personal, so changing to WPA2-PSK does not meet the requirement. Also, VLAN 20 is the wrong VLAN.

C

The specific factual error is that the SSID is currently hidden and the client cannot see it; enabling broadcast is required, not disabling.

D

The specific factual error is that WPA3-Personal uses a pre-shared key, while WPA3-Enterprise requires 802.1X authentication. The client is configured for Personal mode.

Why candidates pick the wrong answer

B

Candidates might pick this if they overlook the client's WPA3 requirement and mistakenly think WPA2 is sufficient, or if they confuse the current VLAN with the desired one.

C

Candidates might think hiding the SSID adds security and choose to keep it hidden, but the client needs the SSID to be broadcast to associate.

D

Candidates might confuse WPA3-Personal with WPA3-Enterprise, or think that Enterprise is always better, but the client's configuration dictates Personal.

1325
MCQhard

An administrator has just configured OSPF in a single area between router R1 and router R2, which are directly connected via their Gi0/0 interfaces with IP addresses 10.0.0.1/30 and 10.0.0.2/30. On R1, the command show ip ospf neighbor shows no entries, and a further check on R2 with show ip ospf interface gi0/0 indicates that the interface is passive. Which configuration error is most likely causing the adjacency failure?

A.The network command on R1 does not cover the 10.0.0.0/30 subnet.
B.R2 has the passive-interface default command but no no passive-interface command for Gi0/0.
C.The OSPF process IDs on R1 and R2 are mismatched.
D.The hello and dead intervals on R1 and R2 are not the same.
AnswerB

The passive-interface default command sets all OSPF interfaces to passive mode. To allow neighbor adjacency on a specific interface, a no passive-interface <interface> command is required. Without it, Gi0/0 remains passive, preventing OSPF hellos and adjacency formation.

Why this answer

The output on R2 shows the Gi0/0 interface is passive, meaning OSPF will not send or receive hello packets on that interface, preventing neighbor discovery. The passive-interface default command makes all interfaces passive by default, and without a no passive-interface Gi0/0 command, the interface remains passive, blocking adjacency formation. This directly explains why R1's show ip ospf neighbor shows no entries.

Exam trap

Cisco often tests the distinction between passive-interface default and the need for explicit no passive-interface commands, as candidates may assume that OSPF will automatically form adjacencies on directly connected interfaces without considering passive configuration.

Why the other options are wrong

A

This option fails to account for the explicit passive interface state shown on R2. A missing network statement would not cause the interface to be displayed as passive; it would simply not be enrolled in the OSPF process.

C

This is a common misconception, but process ID mismatch does not affect OSPF neighbor formation. The passive interface status on R2 directly contradicts this as the cause.

D

The passive interface status would not appear if the only issue were interval mismatches; the interface would still be active and sending hellos. This directly conflicts with the given show output.

1326
MCQhard

A Layer 2 switch port connected to an end host should move to forwarding quickly but also shut down if a BPDU is received. Which pair of features best supports that design?

A.PortFast and BPDU Guard
B.Root Guard and UDLD
C.Loop Guard and native VLAN
D.Port security and EtherChannel
AnswerA

PortFast immediately transitions an access port to the forwarding state, bypassing the listening and learning STP states so the end host can start sending traffic without delay. BPDU Guard protects the STP topology by disabling any PortFast port that receives a BPDU, which indicates an unauthorized switch or bridge has been connected. Together they are the required configuration for a trusted edge port attached to a single end host.

Why this answer

PortFast and BPDU Guard are the right pair. In plain language, PortFast makes an edge port usable quickly for a real end device, while BPDU Guard protects that same port by shutting it down if spanning-tree control traffic appears unexpectedly.

This is a classic access-layer design. PortFast improves usability, and BPDU Guard improves safety. The best answer combines both functions.

Exam trap

Be careful not to confuse BPDU Guard with Root Guard or Loop Guard, as they serve different purposes in spanning tree protection.

Why the other options are wrong

B

Root Guard and UDLD do not directly address the requirement for a port to quickly transition to forwarding while shutting down upon receiving a BPDU. Root Guard is used to prevent a port from becoming a root port, while UDLD is for detecting unidirectional links.

C

Loop Guard and native VLAN do not directly address the requirement for a port to quickly transition to forwarding while shutting down upon receiving a BPDU. Loop Guard is designed to prevent loops by keeping a port in a loop-inconsistent state, and native VLAN is related to VLAN tagging, not port state management.

D

Port security and EtherChannel do not directly address the need for a switch port to quickly transition to forwarding mode while also shutting down upon receiving a BPDU. Port security focuses on limiting MAC addresses and EtherChannel is used for link aggregation, neither of which fulfill the specific requirements of this question.

When would these options actually be correct?

B

In a scenario where the question asks for features that prevent a switch port from becoming a root port while also ensuring link integrity, Root Guard would be appropriate. For example, a question might focus on maintaining a stable root topology in a network with multiple switches.

C

In a scenario where the question asks for features that prevent loops in a network with redundant paths, Loop Guard could be the correct answer. For instance, if the question specifies maintaining network stability while allowing certain VLAN configurations, this option would be appropriate.

D

In a scenario where the question asks for features that enhance security and stability on a switch port, specifically in a multi-link environment, 'Port security and EtherChannel' could be correct. For example, if the question emphasizes preventing unauthorized devices while allowing multiple links for redundancy, this option would be valid.

Why candidates pick the wrong answer

B

Candidates may choose this option because they recognize the need for stability in a spanning tree environment and associate Root Guard with preventing topology changes, leading to confusion about its applicability in the context of BPDU handling.

C

Candidates may find this option tempting because they recognize the importance of preventing network loops and may mistakenly believe that Loop Guard is relevant to the overall stability of Layer 2 switching, even though it does not fulfill the specific requirements of the question.

D

Candidates might choose this option because they recognize the importance of securing switch ports and may mistakenly associate EtherChannel with improved performance and reliability, leading them to believe it fits the question's context.

1327
MCQhard

After configuring the area 0 range 10.0.0.0 255.255.0.0 command on an OSPF ABR, a technician finds that a host at 10.0.5.100 in Area 1 cannot reach hosts in Area 0. The ABR’s OSPF database shows only the summary 10.0.0.0/16 in Area 0, and no individual /24 routes. What is the most likely cause?

A.The ABR is filtering the specific /24 routes using a distribute-list under the OSPF process.
B.The routers in Area 1 are no longer advertising their /24 routes to the ABR because the ABR is in a different area.
C.The area range command causes the ABR to advertise only the summary LSA and suppress the more-specific Type-3 LSAs for the range.
D.The ABR has automatically created a discard route to null0 for the summary, which is dropping all traffic destined to the summarized networks.
AnswerC

By default, the area range command summarizes the specified prefix range and suppresses the individual component routes from being advertised into the target area. Only the summary LSA appears in Area 0, which matches the observed behavior.

Why this answer

The `area 0 range 10.0.0.0 255.255.0.0` command on an OSPF ABR creates a single Type-3 summary LSA (10.0.0.0/16) for Area 0 and suppresses the advertisement of more-specific Type-3 LSAs (e.g., /24 routes) that fall within that range. This is the intended behavior of the `range` command: it summarizes routes at the ABR and prevents the individual component routes from being advertised into the backbone area. Since the host at 10.0.5.100 in Area 1 relies on those specific /24 routes to reach destinations in Area 0, the suppression breaks connectivity.

Exam trap

Cisco often tests the misconception that the `area range` command only summarizes routes without suppressing the more-specific LSAs, leading candidates to incorrectly attribute the connectivity loss to filtering or routing issues rather than the intended suppression behavior.

Why the other options are wrong

A

A distribute-list requires explicit configuration; its absence makes this an unsubstantiated guess.

B

Area border routers receive all LSAs from non-backbone areas; the area boundary does not stop LSA propagation to the ABR itself.

D

The null0 route is a loop-prevention mechanism, not an absolute traffic blocker; more-specific entries in the routing table take precedence.

1328
PBQhard

You are connected to R1 via the console. The network administrator reports that PC1 (connected to R1's GigabitEthernet0/1) cannot reach the internet. Troubleshoot the issue step by step. The current configuration and show outputs are provided.

Hints

  • Check if PC1 can ping the default gateway and the next-hop router.
  • Verify R1's default route.
  • If all local connectivity works, the issue is likely beyond R1 (ISP side).
A.PC1 has an incorrect default gateway configured.
B.R1 is missing a default route to the ISP.
C.routing or NAT issue beyond the local network
D.PC1 has a DNS resolution issue.
AnswerC
solution
! R1

Why this answer

The issue is that PC1 cannot reach the internet despite having correct IP, gateway, and DNS. PC1 can ping the default gateway and even the next-hop router (203.0.113.2), but fails to ping 8.8.8.8. This indicates that the problem is beyond the local network — likely a routing or NAT issue on the ISP side.

However, the task requires troubleshooting client connectivity; the provided outputs show no misconfiguration on PC1 or R1. The fault is external (ISP not routing or no NAT), but the candidate must verify that client configuration is correct and then escalate or check the ISP link. For the PBQ, the candidate should confirm that PC1's IP, subnet mask, gateway, and DNS are correct, and that R1 has a default route and can reach the next hop.

No configuration changes are needed on R1 or PC1; the problem is outside the scope of the local network.

Exam trap

The trap is that candidates may focus on local misconfigurations (gateway, DNS, routing) when the evidence shows local connectivity works. Always verify step by step: if the client can ping the gateway and next hop, the problem is external.

Why the other options are wrong

A

The specific factual error is that a reachable gateway implies correct configuration; if the gateway were wrong, pinging it would fail.

B

The specific factual error is that reachability to the next hop requires a route; if R1 were missing a default route, it could not forward packets to the next hop.

D

The specific factual error is that DNS is only needed for name resolution; pinging an IP address bypasses DNS entirely.

Why candidates pick the wrong answer

A

Candidates often assume that internet connectivity issues are due to a misconfigured gateway, but the ability to ping the gateway rules this out.

B

Candidates often suspect missing default routes when internet access fails, but the ability to ping the next hop confirms routing is working.

D

Candidates often confuse internet connectivity issues with DNS problems, but the use of an IP address eliminates DNS as a factor.

1329
PBQmedium

You are connected to R1 via console. R1 has two upstream paths to the Internet: a primary via ISP1 (G0/0 10.1.1.1/30) and a backup via ISP2 (G0/1 10.2.2.1/30). The backup path should only be used when the primary fails. The default route to ISP1 has been configured, but you must now configure a floating static default route to ISP2 with an administrative distance of 200.

Network Topology
G0/010.1.1.1/30G0/110.2.2.1/30R1ISP1ISP2

Hints

  • Floating static routes use a higher administrative distance to serve as backups.
  • The AD of a static route defaults to 1; to make it floating, set it higher than the primary route's AD.
  • The command format is 'ip route [network] [mask] [next-hop] [distance]'.
A.ip route 0.0.0.0 0.0.0.0 10.2.2.2 200
B.ip route 0.0.0.0 0.0.0.0 10.2.2.1 2
C.ip route 0.0.0.0 0.0.0.0 10.2.2.1 1
D.ip route 0.0.0.0 0.0.0.0 10.2.2.1 250
AnswerA
solution
! R1
ip route 0.0.0.0 0.0.0.0 10.2.2.2 200

Why this answer

A floating static route ensures backup connectivity by using an administrative distance (AD) higher than the primary route's AD. Here, the primary default route has an AD of 1, so the backup must be configured with AD 200 as specified. Crucially, the next-hop address must be the ISP's IP address (10.2.2.2) in the /30 subnet, not R1's own interface IP (10.2.2.1).

Using the local interface IP creates an invalid static route. Option A is correct only with the next-hop set to 10.2.2.2. Options B and C fail because they use AD 2 and 1 respectively (not the required 200) and also point to the wrong next-hop.

Option D uses AD 250 instead of 200 and has the same next-hop error.

Exam trap

The key trap is confusing administrative distance values. Candidates often forget that the backup route must have a higher AD than the primary. They might use the same AD (causing ECMP) or a lower AD (making it preferred).

Also, they might misremember the exact AD value specified in the question. Always ensure the floating static route's AD is explicitly set higher than the primary route's AD.

Why the other options are wrong

B

Uses AD 2 instead of the specified AD 200 and a wrong next-hop of 10.2.2.1.

C

Uses AD 1 (equal to the primary route's AD), preventing failover, and a wrong next-hop of 10.2.2.1.

D

Uses AD 250 instead of the required AD 200 as specified in the question, and still uses the wrong next-hop.

Why candidates pick the wrong answer

B

Candidates might confuse the administrative distance value or think a lower AD is better for backup, not realizing that the backup must have a higher AD than the primary.

C

Candidates may think that setting the same AD as the primary is acceptable or may not understand that floating static routes require a higher AD.

D

Candidates might think a higher AD is always better for backup or may confuse the AD value with other common values like 250 used for some special routes.

1330
MCQhard

A user reports that their computer cannot access the network. The technician checks the computer's IP configuration and finds an APIPA address (169.254.x.x). The computer is connected to a switch port on VLAN 20. The DHCP server is located on VLAN 1. The technician then examines the router's interfaces using 'show ip interface brief' and sees that all interfaces shown are up/up. What should the technician do next?

A.Check the DHCP server logs to see if it is receiving Discover messages.
B.Verify that the ip helper-address command is configured on the router's VLAN 20 interface.
C.Attempt to ping the DHCP server's IP address from the host's APIPA address.
D.Restart the DHCP service on the server and recheck the host.
AnswerB

The router is the intervlan router, and the DHCP server is on a different subnet. For a DHCP Discover broadcast to cross VLANs, the router must have an IP helper-address pointing to the DHCP server's IP address on the VLAN 20 interface. Since all ports are up/up, the problem is almost certainly the missing relay. Checking this config directly addresses the most probable cause.

Why this answer

The APIPA address (169.254.x.x) indicates the host failed to obtain a DHCP lease. Since the DHCP server is on VLAN 1 and the host is on VLAN 20, a DHCP relay (ip helper-address) must be configured on the router's VLAN 20 interface to forward DHCP broadcast messages to the server. The 'show ip interface brief' shows all interfaces are up/up, so the next logical step is to verify the relay configuration.

Exam trap

Cisco often tests the concept that a DHCP relay (ip helper-address) is required when the DHCP server is on a different subnet, and candidates mistakenly focus on server-side issues or ping tests instead of the router configuration.

Why the other options are wrong

A

This action assumes the DHCP request has already reached the server; it bypasses verifying the network path that would deliver the broadcast to the server, which is the most likely missing piece.

C

Candidates might think that if the ping fails, the problem is network connectivity, but APIPA addresses are non-routable and the test itself is invalid in this context.

D

Many techs jump to rebooting a service when a simple configuration check would reveal the real problem. This violates the principle of least intrusive troubleshooting.

1331
Drag & Dropmedium

Drag and drop the following steps into the correct order to describe how data is encapsulated as it travels down the OSI model layers.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

Data originates at the application layer as user data. The transport layer then encapsulates this data by adding a header (e.g., TCP or UDP) to create a segment. The network layer further adds an IP header to the segment, forming a packet.

Next, the data link layer appends a frame header and trailer to the packet, resulting in a frame. Finally, the physical layer converts the entire frame into bits for electrical, optical, or radio transmission. This sequence follows the standard top-down encapsulation process in network communication.

1332
MCQhard

A network administrator has configured a switch port to support a VoIP phone and a desktop PC. Users report that the desktop PC cannot obtain an IP address via DHCP, while the VoIP phone registers successfully. The switch port is up/up, and the desktop is connected to the phone's PC port. What is the most likely cause of the issue?

A.The switchport mode access should be changed to switchport mode trunk to allow both vlans.
B.The switchport access vlan should be changed to the data VLAN to match the subnet expected by the desktop.
C.The switchport voice vlan should be removed because the desktop cannot use it.
D.The spanning-tree portfast should be disabled to prevent DHCP delays.
AnswerB

In a typical IP phone daisy-chain topology, the desktop connects to the phone's PC port, and the switch sends all untagged desktop frames into the port's configured access VLAN. If that access VLAN is incorrectly set to, say, the native VLAN or a different number, the desktop's DHCP DISCOVER will not arrive at the DHCP server for its expected data subnet, leaving it without an IP address. Correctly changing the switchport access vlan to the data VLAN ensures the desktop's untagged traffic is placed in the proper L2 domain, allowing the DHCP server to respond with an appropriate address.

Why this answer

The desktop PC obtains its IP address from the data VLAN, but the switch port's access VLAN is likely misconfigured to the voice VLAN. Changing the access VLAN to the correct data VLAN places the PC in the proper subnet and allows DHCP to function. Option A is unnecessary because a voice-access port does not need to be a trunk.

Option C would break the VoIP phone without fixing the PC's VLAN assignment. Option D is irrelevant; PortFast speeds up STP convergence and does not block DHCP.

Exam trap

Cisco often tests the misconception that the PC uses the voice VLAN or that the port must be a trunk, when in reality the phone handles the VLAN separation internally and the switch port remains an access port with a separate voice VLAN.

Why the other options are wrong

A

The current configuration uses access mode with voice vlan, which is correct for a phone+PC setup. Trunk mode is unnecessary and could break the phone's untagged traffic expectations.

C

The voice vlan is correctly configured for the phone; the problem is with the data vlan assignment for the desktop.

D

Portfast is beneficial for host ports; disabling it would worsen the issue by introducing STP convergence delays.

1333
MCQmedium

Why is multifactor authentication generally stronger than password-only access?

A.It removes the need for authorization policies.
B.It relies on more than one authentication factor.
C.It guarantees that credentials can never be phished.
D.It replaces encryption on the network.
AnswerB

Multifactor authentication (MFA) is stronger because it requires the user to present at least two independent authentication factors, typically from the categories of knowledge (something you know, e.g., a password), possession (something you have, e.g., a smart card or OTP token), and inherence (something you are, e.g., a fingerprint). By combining factors, an attacker must compromise multiple distinct mechanisms, which dramatically reduces the likelihood of successful unauthorized access compared to relying on a single factor that could be stolen, guessed, or reused.

Why this answer

MFA combines independent factors, so compromise of one factor does not automatically grant access.

Exam trap

A common exam trap is selecting options that overstate MFA’s capabilities, such as assuming it guarantees immunity to phishing or replaces encryption. MFA reduces risk but does not eliminate all attack vectors, and it does not substitute for encryption protocols that protect data in transit. Another trap is confusing authentication with authorization; MFA strengthens authentication but does not remove the need for proper authorization policies.

Recognizing these distinctions is critical to avoid incorrect answers that exaggerate MFA’s role or misunderstand its function in network security.

Why the other options are wrong

A

Option A is incorrect because multifactor authentication strengthens authentication processes but does not remove the need for authorization policies. Authorization controls determine what an authenticated user can access, which remains essential regardless of the authentication method.

C

Option C is incorrect because while MFA reduces the risk of phishing attacks by requiring multiple factors, it does not guarantee that credentials can never be phished. Attackers may still find ways to bypass or trick users into revealing multiple factors.

D

Option D is incorrect because authentication methods like MFA do not replace encryption on the network. Encryption protects data confidentiality and integrity during transmission, which is a separate security function from verifying user identity.

When would these options actually be correct?

A

In a different exam question asking about the benefits of simplifying security protocols, an option stating that MFA removes the need for authorization policies could be correct if the context implies a scenario where MFA is used to streamline access control, reducing reliance on complex policies.

C

In a different exam scenario, a question might ask if multifactor authentication completely prevents phishing attacks. In this context, an answer stating that it guarantees credentials can never be phished could be deemed correct if the question implies that the presence of multiple factors significantly mitigates the risk.

D

In a question asking about the benefits of multifactor authentication in relation to data transmission security, one might argue that it enhances security by ensuring that even if data is intercepted, unauthorized access is still prevented. In this context, the answer could be seen as correct if it implies that multifactor authentication contributes to overall security measures, including encryption.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of how MFA integrates with security frameworks, mistakenly believing that adding MFA simplifies overall security management by eliminating the need for policies.

C

Candidates may choose this option due to a common misconception that multifactor authentication inherently protects against all forms of credential theft, leading them to believe it provides absolute security against phishing.

D

Candidates may find this option tempting because they might confuse multifactor authentication with other security measures like encryption, thinking that both are interchangeable solutions for securing data access.

1334
MCQhard

A technician is troubleshooting an OSPF network. On a broadcast segment, R1 is the DR and R2 is the BDR. R1's interface GigabitEthernet0/0 is shut down for maintenance. The technician expects that R2 will assume the DR role, but instead a new DR election occurs and another router is elected DR. What is the most likely cause?

A.The OSPF hello and dead intervals on R2 do not match those of other routers on the segment.
B.R2 has an OSPF priority of 255.
C.The OSPF network type on the segment was changed to point-to-point.
D.R2 has an OSPF priority of 0.
AnswerD

On a broadcast OSPF network, a priority of 0 makes a router ineligible for DR or BDR election. Even though R2 was the BDR, its priority of 0 prevents it from taking over as DR when R1 fails. Consequently, a new DR election is triggered among the remaining eligible routers, and a router other than R2 becomes the new DR.

Why this answer

When the DR (R1) goes down, a new DR election occurs. R2 is the BDR, but if its OSPF priority is 0, it is ineligible to become the DR. Therefore, a new election takes place among the remaining routers with non-zero priorities, and another router wins the DR role.

Exam trap

Cisco often tests the misconception that the BDR automatically becomes DR when the DR fails, but the BDR only takes over if it has a non-zero priority; otherwise, a new election is triggered.

Why the other options are wrong

A

Neighbor adjacency failure due to timer mismatch would have prevented R2 from becoming BDR at all.

B

High priority increases the chance of being elected DR, not decrease it.

C

Point-to-point networks do not have DR/BDR elections, so R2 could not have been BDR.

1335
Multi-Selectmedium

A script authenticates to a controller API and receives a token that it presents in later requests. Which two statements about that token-based workflow are correct?

Select 2 answers
A.The token is often sent in an HTTP header in subsequent requests
B.The token proves identity for that authenticated session or request set
C.The token changes the API from REST to SNMP
D.The token must be stored in the router startup-config
AnswersA, B

The token is typically included in the Authorization header of subsequent HTTP requests, often using the Bearer authentication scheme. This allows the controller API to validate the token and associate the request with the previously authenticated session without re-prompting for credentials. Stateless API servers rely on this per-request header transmission to maintain authentication context across multiple REST calls.

Why this answer

After authentication, many APIs issue a token that the client includes in later HTTP requests. That token acts as proof that the client already authenticated successfully.

Exam trap

A common exam trap is assuming that the presence of a token changes the network management protocol from REST to SNMP or another protocol. This is incorrect because token-based authentication is a security mechanism layered on top of the existing API protocol and does not alter it. Another trap is believing that tokens must be stored in the router’s startup-config, which is false since tokens are ephemeral credentials managed by client applications, not static device configurations.

Misunderstanding these points can lead to selecting incorrect answers about token workflows in automation scenarios.

Why the other options are wrong

C

Option C is incorrect because the token does not change the API protocol from REST to SNMP; authentication methods do not alter the underlying management protocol.

D

Option D is incorrect because tokens are managed dynamically by client applications and are not stored in router startup-config files, which hold static device configurations.

When would these options actually be correct?

C

If the question asked about a scenario where a network device's configuration is changed from using REST API to SNMP for management, then an option stating that the API changes from REST to SNMP could be correct, but that would involve reconfiguration, not a token.

D

If the question asked about storing API credentials for device management (e.g., SNMP community strings or RADIUS keys) that must survive reboots, then storing them in startup-config would be correct.

Why candidates pick the wrong answer

C

Candidates may confuse token-based authentication with protocol conversion, or mistakenly think that tokens can alter API behavior.

D

Candidates may confuse token-based authentication with device configuration persistence, assuming tokens must be saved like passwords or keys in startup-config.

1336
MCQhard

Based on the exhibit, which action is most likely required to allow AP-22 to join the controller successfully?

A.Correct the AP's default gateway so it matches the AP's actual subnet and reachability needs.
B.Change the AP from Ethernet to PPP encapsulation.
C.Remove the AP IP address so it can obtain an IP address automatically via DHCP.
D.Disable DHCP on the controller for all APs.
AnswerA

The AP's IP address and its default gateway must reside in the same Layer 3 subnet; the exhibit shows a mismatch, so the AP cannot route CAPWAP discovery or join messages toward the wireless LAN controller. With an incorrect gateway, the AP's forwarding table sends management traffic to a non-existent or unreachable next hop, effectively isolating the AP from the controller. Correcting the gateway to match the actual subnet and reachability path restores proper IP routing and allows the AP to complete the join process.

Why this answer

The correct action is to fix the AP's default gateway so it can reach the controller's subnet. Option B is wrong because APs use Ethernet, not PPP encapsulation, which is used for serial WAN links. Option C is wrong because CAPWAP does not assign IP addresses; DHCP does, but the AP already has a static IP, and removing it would cause it to fall back to DHCP, which may not fix the gateway issue.

Option D is wrong because disabling DHCP on the controller would affect all APs and prevent new APs from obtaining addresses, which is not a targeted fix.

Exam trap

Avoid assuming resets or updates fix network configuration issues; focus on Layer 3 settings like gateways.

Why the other options are wrong

B

APs use Ethernet frames, not PPP encapsulation; PPP is used for serial links.

C

CAPWAP does not assign IP addresses; DHCP handles that, but removing the AP's IP does not correct the gateway mismatch.

D

Disabling DHCP on the controller would break all APs, not just AP-22, and does not address the gateway issue.

When would these options actually be correct?

B

In a different scenario where the exam question specifies that the AP is in a network environment that exclusively supports PPP for WAN connections, changing the AP to PPP encapsulation would be necessary for it to communicate with the controller.

C

In a scenario where an AP is configured with a static IP address that conflicts with another device on the network, removing the AP's IP address could allow CAPWAP to assign a new, non-conflicting IP address automatically, enabling successful communication with the controller.

D

In a scenario where the question specifies that APs are configured with static IP addresses and the controller is set to use only static IPs, disabling DHCP could be the correct action to ensure that no conflicting DHCP assignments occur.

Why candidates pick the wrong answer

B

Candidates might choose this option due to a misunderstanding of encapsulation types and their relevance to AP connectivity, leading them to think that changing encapsulation could resolve connectivity issues.

C

Candidates may choose this option due to a misunderstanding of how CAPWAP operates, believing that removing the IP address would simplify the AP's connection process, especially if they have encountered similar situations in other networking contexts.

D

Candidates may choose this option due to a misunderstanding of DHCP's role in the AP joining process, believing that disabling DHCP would simplify the connection process when, in fact, it complicates it for dynamically assigned IPs.

1337
MCQhard

A host is configured with 192.168.10.129/25. Which subnet contains that host?

A.192.168.10.0/25
B.192.168.10.64/25
C.192.168.10.128/25
D.192.168.10.192/25
AnswerC

A /25 mask uses a 128-bit block size in the fourth octet, so the valid subnets within 192.168.10.0/24 are 192.168.10.0/25 and 192.168.10.128/25. The address .129 is within the upper block's range .128–.255, making it a host in that subnet. Its usable host range is .129–.254 with broadcast .255.

Why this answer

A /25 divides the /24 into two blocks: 0–127 and 128–255. In practical terms, 192.168.10.129 belongs to the upper half, so the containing subnet is 192.168.10.128/25.

This is a simple subnet-boundary question, but it is designed to confirm that you can identify the correct half of the /24 quickly and confidently.

Exam trap

A frequent exam trap is misidentifying the subnet boundaries for a /25 mask within a /24 network. Candidates often mistakenly believe that subnets start at .64 or .192, confusing /25 with other subnet sizes like /26 or /27. This leads to selecting incorrect subnets such as 192.168.10.64/25 or 192.168.10.192/25, which are invalid because /25 only divides the /24 into two halves starting at .0 and .128.

This misunderstanding causes errors in subnet identification and can result in wrong routing or access decisions in real networks.

Why the other options are wrong

A

192.168.10.0/25 covers IP addresses from 192.168.10.0 to 192.168.10.127. Since the host IP is 192.168.10.129, which is greater than .127, it does not belong to this subnet, making this option incorrect.

B

192.168.10.64/25 is not a valid /25 subnet boundary within a /24 network. /25 subnets split at .0 and .128 only, so this option is invalid and cannot contain the host 192.168.10.129.

D

192.168.10.192/25 is not a valid /25 subnet boundary within a /24 network. The /25 mask divides the network into two subnets only, starting at .0 and .128, so this option is incorrect.

When would these options actually be correct?

A

If the question asked which subnet contains the IP address 192.168.10.0/25 and the host IP was changed to 192.168.10.0, then option A would be correct as it would be the subnet that includes the host IP.

B

If the question asked which subnet contains the host 192.168.10.129 with a /24 subnet mask instead, then option B (192.168.10.64/25) would be correct, as it would refer to the second half of the 192.168.10.0/24 subnet, which includes the host IP.

D

If the question asked which subnet contains the IP address 192.168.10.192 with a subnet mask of /25, then option D would be correct. In this case, the question would focus on identifying the subnet for a different host IP address.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of subnetting boundaries, mistakenly believing that the host IP falls within the range of the specified subnet.

B

Candidates may choose this option due to confusion between the subnet ranges, as they might mistakenly associate the 64 in the address with a valid subnet range without fully calculating the subnet boundaries.

D

Candidates might choose this option due to a misunderstanding of subnetting, mistakenly believing that any IP in the same Class C range (192.168.10.x) could belong to the same subnet without considering the specific subnet mask.

1338
MCQhard

Exhibit: An access switch shows Gi1/0/10 as err-disabled shortly after an IP phone and a workstation are connected through the same wall jack. What is the most likely cause?

A.The native VLAN is missing
B.The port security maximum is too low for the connected devices
C.BPDU Guard blocked the port because a workstation was attached
D.DHCP snooping denied the voice VLAN
AnswerB

With a Cisco IP phone and a PC behind it, the switchport must learn two MAC addresses (phone and PC) on the same port. If the port-security maximum is set to 1, the second MAC address triggers a violation and the default violation mode (shutdown) places the interface into err-disabled state. The fix is to raise the maximum to at least 2 and optionally use sticky MAC addresses.

Why this answer

With a phone and a PC on the same access port, the switch may legitimately see two MAC addresses. Port security set to a maximum of 1 causes a violation and can place the interface into err-disabled state.

Exam trap

Be cautious of assuming all err-disabled states are due to STP or VLAN issues; port security is a frequent cause.

Why the other options are wrong

A

The native VLAN being missing would not directly cause a port to go err-disabled when connecting an IP phone and workstation; it typically results in VLAN mismatches or communication issues rather than disabling the port.

C

BPDU Guard is designed to protect against loops by disabling ports that receive Bridge Protocol Data Units (BPDUs). In this scenario, the port is err-disabled due to port security violations, not because of BPDU Guard activation.

D

DHCP snooping denying the voice VLAN would typically result in the IP phone failing to receive an IP address, rather than causing the port to go err-disabled. The err-disabled state is more likely due to port security violations when multiple devices are connected.

When would these options actually be correct?

A

In a scenario where a switch is configured to require a native VLAN for trunking and a device attempts to connect without it, a question could ask about the impact of a missing native VLAN on trunk ports, making this option correct.

C

If the question specified that a switch port was err-disabled due to receiving BPDUs from a connected device, and the context involved a misconfigured spanning tree, then option C would be correct. For example, if a switch was connected to another switch instead of an endpoint device, BPDU Guard could trigger.

D

If the question described a scenario where a switch port was configured with DHCP snooping and the voice VLAN was not properly trusted, leading to the IP phone being unable to obtain an IP address, this option would be correct. In that case, the port could go err-disabled due to DHCP snooping violations.

Why candidates pick the wrong answer

A

Candidates may confuse the concept of native VLANs with port security issues, leading them to believe that a missing native VLAN could cause err-disabled states due to VLAN-related misconfigurations.

C

Candidates may confuse the err-disabled state with security features like BPDU Guard, especially if they have encountered similar scenarios where misconfigurations lead to port shutdowns, leading them to select this option without fully analyzing the context.

D

Candidates may be tempted by this option because they recognize that DHCP snooping can impact device connectivity, and they may confuse the symptoms of connectivity issues with the err-disabled state caused by port security violations.

1339
PBQhard

You are connected to R1. Configure SNMP v2c with a read-only community string 'monitorRO' and a read-write community string 'controlRW', and enable SNMP traps for link status to the management server at 203.0.113.100. Additionally, configure NetFlow to export version 9 flow records to the same server on UDP port 2055, and ensure that only traffic from the 10.10.10.0/24 network is monitored. Finally, verify your configurations with the appropriate show commands.

Network Topology
G0/010.0.0.1/30G0/010.0.0.2/30linkG0/110.10.10.1/2410.10.10.0/24linkR1R2Internal Network

Hints

  • Remember to specify the SNMP version when configuring the trap receiver host.
  • NetFlow version 9 must be explicitly configured; otherwise, version 5 is used by default.
  • Apply the flow monitor to the interface that connects to the network you want to monitor (G0/1).
A.Configure SNMP community strings, enable link-status traps, set trap destination, configure NetFlow export version 9, and apply flow monitor to interface(s) carrying 10.10.10.0/24 traffic.
B.Configure SNMP community strings, enable link-status traps, set trap destination, and configure NetFlow export version 5. Apply flow monitor to all interfaces.
C.Configure SNMP community strings, enable all SNMP traps, set trap destination, and configure NetFlow export version 9. Apply flow monitor to interface with IP 10.10.10.0/24.
D.Configure SNMP community strings, enable link-status traps, set trap destination, and configure NetFlow export version 9. Do not apply any flow monitor; NetFlow automatically monitors all traffic.
AnswerA
solution
! R1
snmp-server community monitorRO RO
snmp-server community controlRW RW
snmp-server enable traps snmp linkdown linkup
snmp-server host 203.0.113.100 version 2c monitorRO
ip flow-export version 9
flow record NETFLOW-RECORD
 match ipv4 source address
 match ipv4 destination address
 match ipv4 protocol
 match transport source-port
 match transport destination-port
 collect counter bytes
 collect counter packets
 collect timestamp sys-uptime
 exit
flow exporter EXPORTER-TO-SERVER
 destination 203.0.113.100
 transport udp 2055
 source Loopback0
 exit
flow monitor MONITOR-10NET
 record NETFLOW-RECORD
 exporter EXPORTER-TO-SERVER
 cache timeout active 300
 exit
interface GigabitEthernet0/1
 ip flow monitor MONITOR-10NET input
 ip flow monitor MONITOR-10NET output
 exit

Why this answer

The solution correctly configures SNMP v2c with the required read-only and read-write community strings, enables only link-status traps, and sets the trap destination. For NetFlow, it uses Flexible NetFlow by defining a flow record, an exporter, and a monitor. Importantly, the export version (9) must be configured under the flow exporter, not with the legacy global `ip flow-export version 9` command.

The flow monitor is applied to GigabitEthernet0/1, which carries traffic from the 10.10.10.0/24 network. Verification can be done with `show snmp` to confirm communities and trap receivers, and `show flow monitor name MONITOR-10NET cache` or `show ip cache flow` to view exported flow records.

Exam trap

Common mistakes include mixing legacy and Flexible NetFlow commands (e.g., using the global `ip flow-export version` instead of setting it under the flow exporter), forgetting to apply the flow monitor to an interface, and enabling all SNMP traps rather than only link-status traps.

Why the other options are wrong

B

The question explicitly requires NetFlow version 9, and traffic monitoring must be limited to the 10.10.10.0/24 network.

C

Enabling all traps is unnecessary and may cause unwanted overhead; the flow monitor must be applied to the correct interface(s) based on traffic flow, not the network address.

D

NetFlow requires a flow monitor to be applied to an interface to capture traffic; it does not automatically monitor all traffic.

Why candidates pick the wrong answer

B

Candidates might default to version 5 because it is the default version, and applying to all interfaces seems simpler.

C

Candidates might think enabling all traps is safer, and misunderstand the interface application as needing the network IP.

D

Candidates might assume that configuring the export destination is sufficient, but the flow monitor must be explicitly applied.

1340
MCQmedium

A network technician is troubleshooting a connectivity issue where a user's email client cannot send messages, but the client can receive emails. The technician uses a protocol analyzer and sees that the client is successfully resolving the mail server's domain name to an IP address and establishing a TCP connection, but the server responds with an application-layer error. At which layers of the OSI model are the problem and the successful operations occurring, respectively?

A.The problem is at the Transport layer (Layer 4); successful operations are at the Application layer (Layer 7) only.
B.The problem is at the Application layer (Layer 7); successful operations are at the Application layer (Layer 7) and Transport layer (Layer 4).
C.The problem is at the Network layer (Layer 3); successful operations are at the Data Link layer (Layer 2) and Physical layer (Layer 1).
D.The problem is at the Presentation layer (Layer 6); successful operations are at the Session layer (Layer 5) and Transport layer (Layer 4).
AnswerB

The sequence of successful operations shows DNS resolution (Application layer, Layer 7) and a TCP handshake to the mail server's port 25 (Transport layer, Layer 4). These two layers are working end-to-end. The mail server returns an SMTP error after the connection is established, such as a rejected recipient or a policy violation. That error is an application-level protocol response, so the fault lies squarely in the Application layer (Layer 7), not in any lower layer.

Why this answer

The problem is at the Application layer (Layer 7) because the email client can resolve the domain name (DNS, Layer 7), establish a TCP connection (Transport layer, Layer 4), but the mail server returns an application-layer error (e.g., SMTP 550 or 554), indicating the issue lies in the email protocol itself (e.g., authentication failure, mailbox full, or rejected sender). Successful operations include DNS resolution (Application layer) and TCP three-way handshake (Transport layer), confirming layers 7 and 4 are functioning correctly.

Exam trap

Cisco often tests the distinction between successful lower-layer operations (DNS, TCP) and an application-layer failure, trapping candidates who assume any email problem must be at the Transport or Network layer because they confuse 'connection established' with 'protocol function working'.

Why the other options are wrong

A

The TCP handshake succeeded, so the Transport layer is working. The error message is generated by the application, not the transport protocol.

C

Successful TCP connection implies IP routing (Layer 3) is working. The error is not related to addressing or routing.

D

Email sending failures are typically application logic errors, not encryption/formatting or session problems. Also, DNS is an Application layer protocol, not Session or Presentation.

1341
Multi-Selectmedium

Which three of the following are correct steps in the process of CDP (Cisco Discovery Protocol) neighbor discovery? (Choose three.)

Select 3 answers
.CDP operates at Layer 2 and sends advertisements to the multicast address 01:00:0C:CC:CC:CC.
.CDP advertisements include the device identifier, platform, and capabilities.
.CDP is enabled by default on Cisco devices and runs over all interfaces that support SNAP headers.
.CDP advertisements are sent every 30 seconds by default.
.CDP can discover devices that are more than one Layer 2 hop away.
.CDP requires that both devices be in the same IP subnet.

Why this answer

CDP is a Cisco proprietary Layer 2 protocol that uses multicast MAC address 01:00:0C:CC:CC:CC to send advertisements to directly connected neighbors. Advertisements include device identifier, platform, and capabilities. CDP is enabled by default on Cisco devices and runs over interfaces supporting SNAP headers.

Incorrect options: CDP advertisements are sent every 60 seconds by default (not 30); CDP discovers only directly connected neighbors (not devices more than one L2 hop away); CDP does not require both devices to be in the same IP subnet because it operates at Layer 2.

Exam trap

A common mistake is thinking CDP uses a broadcast address or operates at Layer 3; another trap is confusing the default CDP timer (60 seconds) with the 30-second timer of other protocols like LLDP.

Why the other options are wrong

D

CDP advertisements are sent every 60 seconds by default, not 30.

E

CDP discovers only directly connected neighbors; it does not propagate beyond one Layer 2 hop.

F

CDP operates at Layer 2 and does not require devices to be in the same IP subnet.

1342
Drag & Drophard

Drag and drop the following steps into the correct order to configure a WLAN for WPA3-Enterprise on a Cisco WLC and sequence a wireless client association process.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

The configuration creates the WLAN with WPA3-Enterprise security, enables it, then the client associates and completes 802.1X authentication before getting an IP.

Exam trap

Do not confuse the order of 802.1X authentication and DHCP. In WPA3-Enterprise, the client must authenticate before obtaining an IP address. Also, remember that a WLAN must be created before it can be enabled, and it must be enabled before clients can associate.

Why candidates pick the wrong answer

B

Candidates might think DHCP is needed for the client to communicate with the authentication server, but in 802.1X, the client uses EAP over wireless before getting an IP.

C

Candidates might think enabling is a separate step that can be done first, but the WLAN must exist in the configuration first.

D

Candidates might think client association can happen before enabling, but the WLAN must be active for clients to see and connect to it.

1343
Matchingmedium

Match each NAT term to its most accurate description.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Private address used by the host on the internal network

Address that represents the internal host to outside networks

Fixed one-to-one translation

Many-to-one translation using ports

Why these pairings

NAT terms describe address perspectives: Inside Local is the internal host's IP, Inside Global is its external IP, Outside Local is the external host's IP seen internally, Outside Global is its actual external IP, Static NAT provides permanent mapping, and Dynamic NAT uses a pool.

Exam trap

The exam trap is confusing the perspective (inside vs. outside) and the location (local vs. global). Remember: 'Local' is the address as seen from the inside network, 'Global' is the address as seen from the outside network.

When would these options actually be correct?

B

If the question asked for the definition of 'Outside Local' (the IP address of an external host as seen from inside the network), then this option would be correct.

C

If the question asked for the definition of 'Inside Global' (the IP address of an internal host as seen from outside the network), then option C would be correct.

D

If the question asked for the definition of 'Outside Local' (the IP address of an external host as seen from outside the network), then option D would be correct.

Why candidates pick the wrong answer

B

Candidates may confuse 'Inside Local' with 'Outside Local' due to similar phrasing, or mistakenly think 'Inside' refers to the location of the host rather than the perspective of the address.

C

Candidates may confuse 'Inside Local' with 'Inside Global' because both involve internal hosts, but they differ in perspective (inside vs. outside the network).

D

Candidates may confuse 'Inside Local' with 'Outside Local' due to similar phrasing, or mistakenly think 'Local' implies the perspective of the local network (outside) rather than the inside host.

1344
MCQhard

Why is a northbound API valuable to orchestration tools in a controller-based network?

A.It gives orchestration tools a defined software interface to interact with the controller.
B.It replaces the need for all physical network devices.
C.It is a cabling standard for data center uplinks.
D.It makes security controls unnecessary.
AnswerA

This is correct because northbound APIs are the application-facing path into the controller.

Why this answer

A northbound API is valuable because it gives orchestration tools a defined way to request data and trigger changes on the controller programmatically. In plain language, the tool can interact with the controller through software rather than relying on manual device-by-device operations. That makes higher-level automation and service coordination possible.

The controller is the platform, and the northbound API is the application-facing interface into it. The correct answer is the one focused on orchestration and software-driven interaction.

Exam trap

A frequent exam trap is mistaking the northbound API for a physical network element or a cabling standard, such as assuming it replaces physical devices or relates to data center uplinks. Another common error is believing that northbound APIs eliminate the need for security controls, ignoring that software interfaces still require authentication and authorization mechanisms. These misconceptions stem from confusing the software abstraction layer with hardware or security concepts.

Understanding that northbound APIs are purely software interfaces designed for orchestration tools to interact programmatically with the controller helps avoid these pitfalls.

Why the other options are wrong

B

Option B is incorrect because northbound APIs do not replace physical network devices; forwarding hardware remains essential for actual data transmission and network operation.

C

Option C is incorrect since northbound APIs are software interfaces, not physical cabling standards, and have no relation to data center uplink cabling specifications.

D

Option D is incorrect because northbound APIs still require security measures such as authentication and authorization; they do not eliminate the need for security controls.

When would these options actually be correct?

B

If the exam question were to ask about the impact of virtualization on network architecture, a candidate might argue that a northbound API reduces reliance on physical devices by enabling virtualized networking solutions, thus making this option correct in that context.

C

If the exam question asked about the physical infrastructure of a data center and specifically inquired about standards for cabling and connectivity, then option C could be correct in that context, as it would refer to a standard like Ethernet cabling for uplinks.

D

In a different context, a question might ask about the implications of using a specific network architecture that inherently includes security features, such as a zero-trust model. In that case, one could argue that traditional security controls are less emphasized due to built-in security mechanisms.

Why candidates pick the wrong answer

B

Candidates may be tempted by this option due to a misunderstanding of how network virtualization works, leading them to believe that APIs can replace hardware rather than enhance management capabilities.

C

Candidates may choose this option due to a misunderstanding of the terminology, confusing network management concepts with physical infrastructure standards, leading to an assumption that cabling is relevant to orchestration tools.

D

Candidates might choose this option due to a misunderstanding of the role of APIs in network management, mistakenly believing that automation and orchestration reduce the need for security measures rather than complementing them.

1345
Multi-Selectmedium

Which two features commonly strengthen access-switch security for user-facing ports? (Choose two.)

Select 2 answers
A.Port security
B.BPDU Guard
C.Administrative distance
D.Route summarization
AnswersA, B

Port security strengthens access switch security by constraining the valid source MAC addresses on an interface, typically to a learned or configured set. When a violation occurs, the switch can either drop the frame, shut down the port, or place it in a restricted state, mitigating MAC flooding and unauthorized device attachment. This feature is applied at Layer 2 on access ports, directly controlling end-station connectivity.

Why this answer

Port security can limit learned MAC addresses, and BPDU Guard can shut down an edge port that unexpectedly receives BPDUs.

Exam trap

A common exam trap is selecting administrative distance or route summarization as security features for user-facing access ports. Administrative distance is a routing protocol metric used to select the best path and has no role in access-switch port security. Similarly, route summarization is a routing optimization technique that reduces routing table size but does not affect port security.

Candidates may confuse these routing concepts with security features due to their importance in network design, but they do not strengthen access-switch security for user-facing ports. Recognizing this distinction is critical to avoid losing points on this question.

Why the other options are wrong

C

Administrative distance is a routing protocol metric used to select the best path and does not relate to access-switch port security. It does not control port access or prevent unauthorized devices, so option C is incorrect.

D

Route summarization is a routing optimization technique that reduces routing table size and update traffic. It does not provide any security controls for user-facing switch ports, so option D is incorrect.

When would these options actually be correct?

C

If the question were about routing protocols and their configurations, asking which feature affects the selection of routes, administrative distance would be the correct answer as it helps routers choose the best path based on the trust level of the routing information.

D

In a question focused on optimizing routing protocols and reducing routing table size, such as 'What technique can be used to minimize routing updates in a large network?', route summarization would be the correct answer as it effectively summarizes multiple routes into a single advertisement.

Why candidates pick the wrong answer

C

Candidates may confuse administrative distance with security measures, thinking that it relates to controlling access or managing user connections, leading them to mistakenly select it as a security feature.

D

Candidates may confuse route summarization with network security concepts, thinking that reducing routing information could somehow relate to securing access ports, especially if they have limited understanding of specific switch security features.

1346
MCQmedium

Exhibit: A user reports intermittent connectivity after a new switch was connected to an access port. Which feature would have prevented this by immediately disabling the port when a BPDU was received?

A.Root Guard
B.Loop Guard
C.BPDU Guard
D.UDLD
AnswerC

BPDU Guard is the correct protection mechanism because it is designed specifically for PortFast-enabled access ports. When a legitimate BPDU is received on such a port, BPDU Guard immediately err-disables the interface to prevent a potential bridging loop, which explains the intermittent connectivity: the new device is sending BPDUs and triggering the shutdown each time.

Why this answer

BPDU Guard is the correct answer because it protects PortFast-enabled edge ports by immediately disabling the port upon receiving a BPDU, preventing accidental loops. Root Guard prevents the port from becoming a root port, not from BPDU reception. Loop Guard prevents alternate or root ports from becoming designated due to BPDU loss, unrelated to BPDU reception disabling.

UDLD detects unidirectional links but does not disable ports upon BPDU reception.

Exam trap

Be cautious not to confuse BPDU Guard with other guard features like Root Guard or Loop Guard, which serve different purposes.

Why the other options are wrong

A

Root Guard prevents a port from being elected as root port, not from receiving BPDUs on an access port.

B

Loop Guard prevents loops caused by BPDU loss on blocked ports, not from BPDU reception on access ports.

D

UDLD detects unidirectional links but does not disable a port when a BPDU is received.

When would these options actually be correct?

A

In a different question, if the scenario involved preventing a non-root switch from becoming the root bridge while allowing the existing root bridge to maintain its status, Root Guard would be the correct answer. For example, if a user was asked how to secure the root bridge in a network with multiple switches, Root Guard would be appropriate.

B

In a different question, if the scenario involved a network topology where a switch was incorrectly configured and caused a loop, asking about preventing loops without specifying immediate port disablement could make Loop Guard the correct answer, as it would maintain stability by preventing loops.

D

In a scenario where a question asks about how to prevent unidirectional links from causing network issues, and it specifies that a port should be disabled when a unidirectional link is detected, UDLD would be the correct answer.

Why candidates pick the wrong answer

A

Candidates may confuse Root Guard with BPDU Guard due to their similar functions related to BPDUs, leading them to mistakenly believe that Root Guard also provides immediate port shutdown capabilities.

B

Candidates may choose Loop Guard because they associate it with BPDU handling and network stability, leading them to believe it could address issues related to connectivity and loops, despite it not directly disabling ports upon BPDU reception.

D

Candidates may confuse UDLD with BPDU Guard due to both being related to link stability and port management, leading them to mistakenly believe UDLD could also prevent issues caused by BPDUs.

1347
PBQhard

You are connected to R1 via console. The link between R1 and R2 is experiencing packet loss and CRC errors. Configure interface speed and duplex on R1's GigabitEthernet0/0 to match R2's settings, then replace the SFP module with one that supports the required 2 km distance. Finally, verify the interface is operational without errors.

Network Topology
G0/0192.0.2.1/30G0/0192.0.2.2/302km fiberR1R2

Hints

  • CRC errors often indicate a duplex mismatch. Check the neighbor's configuration.
  • Auto-negotiation must be disabled on both ends if one side is hardcoded.
  • The current SFP is rated for 550m; for 2 km you need a long-range SFP (e.g., 1000BASE-LX).
A.Configure speed 1000, duplex full, and no negotiation auto on Gi0/0, then replace the SFP-GE-SX with SFP-GE-L.
B.Configure speed 1000 and duplex full on Gi0/0, then replace the SFP-GE-SX with SFP-GE-SX-MM.
C.Configure speed 100 and duplex full on Gi0/0, then replace the SFP-GE-SX with SFP-GE-L.
D.Configure no negotiation auto on Gi0/0, then replace the SFP-GE-SX with SFP-GE-L.
AnswerA
solution
! R1
configure terminal
interface GigabitEthernet0/0
speed 1000
duplex full
no negotiation auto
end
copy running-config startup-config

Why this answer

The CRC errors indicate a duplex mismatch or faulty medium. R1 is set to auto-negotiation while R2 is hardcoded to 1000/full, causing mismatch. First, set speed and duplex on R1 to match R2: 'speed 1000' and 'duplex full'.

Also disable auto-negotiation with 'no negotiation auto'. The existing SFP-GE-SX only supports 550m, but the link requires 2 km; replace it with a 1000BASE-LX/LH SFP (SFP-GE-L) which supports up to 10 km. After changes, verify with 'show interfaces Gi0/0' to confirm no CRC errors and correct speed/duplex.

Exam trap

Do not forget to disable auto-negotiation when manually setting speed and duplex on a Cisco interface. Also, remember that SFP types have specific distance limitations: SX for short reach (550m), LX/LH for long reach (10 km), and EX or ZX for even longer distances.

Why the other options are wrong

B

The SFP-GE-SX-MM is a multimode SFP with the same distance limitation as the original SFP-GE-SX.

C

The speed must match exactly; 100 Mbps is not compatible with 1000 Mbps.

D

When auto-negotiation is disabled, speed and duplex must be manually set; otherwise, the interface may default to half-duplex or other incompatible settings.

Why candidates pick the wrong answer

B

Candidates might think 'MM' stands for 'more' or 'medium' and assume it supports longer distances, but it actually stands for multimode.

C

Candidates might confuse speed settings or think that 100/full is a common setting for older links.

D

Candidates might think that disabling auto-negotiation alone is sufficient to match a hardcoded interface, but the speed and duplex must also be explicitly configured.

1348
MCQhard

A monitoring system already collects Syslog and SNMP data. The network team now wants visibility into which applications or host conversations are driving link utilization. What is the strongest addition?

A.NetFlow
B.Another SSID
C.PortFast
D.A larger wildcard mask
AnswerA

NetFlow is correct because it captures metadata about traffic flows — including source/destination IPs, ports, and protocol — and exports that data to a collector for analysis. This gives the monitoring system detailed, flow-level visibility into who is talking to whom and how much bandwidth each conversation uses, which syslog and SNMP alone cannot provide. NetFlow complements existing syslog and SNMP data by focusing on network traffic patterns rather than device logs or interface counters.

Why this answer

The strongest addition is NetFlow because it provides traffic-flow visibility. In practical terms, Syslog and SNMP are useful, but they do not directly answer detailed conversation-level questions such as which hosts, protocols, or flows are consuming the most bandwidth. NetFlow is designed to answer exactly that kind of question.

This is about choosing the right operational tool for the visibility gap.

Exam trap

A frequent exam trap is selecting options like PortFast or adding another SSID, which are unrelated to traffic flow monitoring. PortFast is an STP feature that speeds up port transitions but does not provide any insight into bandwidth usage or application-level traffic. Similarly, adding another SSID only affects wireless network segmentation and does not offer visibility into which hosts or applications consume bandwidth.

Another trap is thinking that changing ACL wildcard masks can help analyze traffic flows, but ACLs only filter traffic and do not provide analytics. Recognizing that only NetFlow delivers detailed flow-level data prevents these common mistakes.

Why the other options are wrong

B

Adding another SSID is incorrect because it only creates a new wireless network segment and does not provide any traffic flow or bandwidth usage information. It does not help identify which applications or hosts are using the link.

C

PortFast is an STP feature that speeds up port transitions on edge ports but does not monitor or analyze traffic flows. It has no relevance to identifying bandwidth usage or application-level visibility.

D

Using a larger wildcard mask in ACLs affects traffic filtering rules but does not provide analytics or visibility into traffic flows. ACLs do not report on bandwidth consumption or application usage.

When would these options actually be correct?

B

If the question asked about improving wireless network segmentation or isolating traffic types for security purposes, then adding another SSID could be the correct answer, as it would allow for different access controls and traffic management.

C

If the question were focused on optimizing switch port performance in a network with many end devices connecting and disconnecting frequently, PortFast would be the correct answer. In that context, it would help reduce downtime for devices connecting to the network.

D

In a question focused on configuring access control lists (ACLs) for specific traffic filtering in a routing scenario, a larger wildcard mask could be the correct answer, as it allows for more flexible matching of IP addresses.

Why candidates pick the wrong answer

B

Candidates may confuse the need for visibility into network traffic with the idea of segmenting traffic through SSIDs, believing that creating separate networks could help manage or monitor utilization effectively.

C

Candidates might choose PortFast because they associate it with improving network performance and efficiency, which could lead them to mistakenly believe it relates to monitoring link utilization.

D

Candidates may confuse the concept of wildcard masks with traffic analysis, thinking that adjusting the mask could help in identifying or managing traffic flows, despite it being unrelated to application-level visibility.

1349
MCQhard

A host address is 172.22.14.99/27. Which address is the broadcast address of the subnet?

A.172.22.14.95
B.172.22.14.127
C.172.22.14.96
D.172.22.14.128
AnswerB

172.22.14.127 is the broadcast address for the /27 subnet that contains host 172.22.14.99. Since the /27 mask creates 32-address blocks, the relevant block runs from 172.22.14.96 through 172.22.14.127, and the broadcast is always the final address in that block. The host bits in .127 are all ones, which identifies this as the directed broadcast for this subnet.

Why this answer

A /27 subnet has a block size of 32. In practical terms, the relevant blocks are 0-31, 32-63, 64-95, 96-127, and so on. Because 99 falls within the 96-127 block, the broadcast address is the last address in that block: 172.22.14.127.

This is a classic subnet-boundary question and remains important because addressing precision appears throughout the CCNA blueprint.

Exam trap

Be careful not to confuse network addresses with broadcast addresses, and ensure you are calculating the correct subnet range.

Why the other options are wrong

A

Option A is incorrect because the broadcast address for the subnet 172.22.14.99/27 is 172.22.14.127, not 172.22.14.95. The /27 subnet mask indicates that the last 5 bits are for host addresses, allowing for a range of addresses that ends at 172.22.14.127.

C

Option C (172.22.14.96) is incorrect because it falls within the usable host range of the subnet and is not the broadcast address. The broadcast address for the subnet 172.22.14.96/27 is actually 172.22.14.127.

D

Option D, 172.22.14.128, is incorrect because it does not fall within the subnet defined by 172.22.14.99/27, which has a valid range of 172.22.14.96 to 172.22.14.127. The broadcast address for this subnet is 172.22.14.127.

When would these options actually be correct?

A

In a different question where the subnet mask was /26 and the host address was 172.22.14.99, option A (172.22.14.95) could be the broadcast address for that subnet. This would occur if the address range was defined such that 172.22.14.64/26 had 172.22.14.95 as its broadcast address.

C

In a different scenario where the subnet mask is changed to /26, the address 172.22.14.96 could be the broadcast address for the subnet 172.22.14.64/26. In this case, the range would include addresses from 172.22.14.65 to 172.22.14.126, making 172.22.14.126 the broadcast address.

D

In a different question where the subnet mask is /25, the broadcast address for the subnet containing 172.22.14.128 would be 172.22.14.255. In this scenario, option D would be the correct answer as it would represent the broadcast address for that specific subnet.

Why candidates pick the wrong answer

A

Candidates may choose option A due to a miscalculation of the subnet range, mistakenly believing that the lower end of the host address range is the broadcast address. This can happen if they confuse the calculation of usable addresses in a subnet.

C

Candidates may choose this option due to confusion between the subnet address and the broadcast address, as they might miscalculate the range of usable addresses and mistakenly identify 172.22.14.96 as a boundary address.

D

Candidates may be tempted by option D because it is a higher address within the same octet, leading them to mistakenly associate it with the broadcast address due to common subnetting patterns.

1350
MCQhard

An administrator deploys a new WLAN on a Cisco 9800 WLC using WPA3-Personal (SAE) with AES encryption. A single 802.11ax laptop running Windows 10 fails to connect, displaying an authentication timeout despite entering the correct passphrase. Other clients, including legacy 802.11ac devices, connect without issue.

A.The WLC’s WLAN is misconfigured for WPA3-Enterprise, and the laptop lacks a supplicant for 802.1X authentication.
B.The laptop’s wireless adapter does not support Protected Management Frames, which are mandatory for WPA3-Personal.
C.The WLC has disabled 802.11ax OFDMA on the 5 GHz band, preventing the 802.11ax laptop from associating.
D.The laptop’s driver is configured for 160 MHz channel width, which is incompatible with the WLC’s channel plan, causing authentication to fail.
AnswerB

For WPA3-Personal, the client and access point must negotiate Protected Management Frames (PMF) as part of the RSN information element during association; PMF is not optional but mandatory in WPA3. If the laptop's wireless adapter does not advertise or enable the Management Frame Protection Capable bit, the WLC cannot complete the handshake, causing SAE authentication to time out. This explains why only this 802.11ax-capable device fails while others succeed—it reflects a client-side capability gap, not a network-wide configuration error.

Why this answer

WPA3-Personal (SAE) mandates the use of Protected Management Frames (PMF) as defined in IEEE 802.11w. If the laptop's wireless adapter or driver does not support PMF, it cannot complete the SAE handshake, resulting in an authentication timeout. Legacy 802.11ac clients can connect because they are using WPA2, which does not require PMF.

Exam trap

Cisco often tests the mandatory dependency of Protected Management Frames (802.11w) for WPA3-Personal, leading candidates to incorrectly attribute the failure to channel width or OFDMA incompatibility.

Why the other options are wrong

A

Misidentifying the WLAN security type: WPA3-Personal does not require an enterprise supplicant, so this is not the cause.

C

Confusing radio resource management with connection establishment: OFDMA settings do not block initial association, only data transmission efficiency.

D

Misattributing connection failures to channel bandwidth settings; these are negotiated after successful association and do not impact the 802.11 authentication and association phases.

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