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CCNA 200-301 v2 (200-301) — Questions 13511389

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

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1351
PBQhard

You are connected to a single switch, SW1, which is a Cisco Catalyst 2960 running Cisco IOS. Configure port GigabitEthernet0/1 as an access port for a Cisco IP phone and a PC on the same VLAN (Voice VLAN 20, Data VLAN 10). The switch must provide PoE to the phone. Additionally, configure GigabitEthernet0/2 as an access port for a wireless access point (AP) that requires PoE. Verify both configurations using the appropriate show commands. The current running-config is incomplete; you must add the necessary commands.

Hints

  • Voice VLAN is configured with a separate command on the interface.
  • PoE may be disabled; use 'power inline auto' to enable it.
  • Use 'show interfaces switchport' to confirm voice VLAN assignment.
A.interface GigabitEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline auto interface GigabitEthernet0/2 switchport mode access switchport access vlan 10 power inline auto
B.interface GigabitEthernet0/1 switchport mode trunk switchport trunk allowed vlan 10,20 power inline auto interface GigabitEthernet0/2 switchport mode access switchport access vlan 10 power inline auto
C.interface GigabitEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline never interface GigabitEthernet0/2 switchport mode access switchport access vlan 10 power inline auto
D.interface GigabitEthernet0/1 switchport mode access switchport access vlan 20 switchport voice vlan 10 power inline auto interface GigabitEthernet0/2 switchport mode access switchport access vlan 10 power inline auto
AnswerA
solution
! SW1
configure terminal
interface gigabitEthernet 0/1
switchport voice vlan 20
power inline auto
exit
interface gigabitEthernet 0/2
power inline auto
end
write memory

Why this answer

The configuration was missing the voice VLAN assignment on Gi0/1 and PoE settings on both ports. For Gi0/1, the command 'switchport voice vlan 20' is required to separate voice traffic from data traffic. For both Gi0/1 and Gi0/2, PoE must be enabled; by default 'power inline auto' is set, but since the ports show 'off', they may have been disabled.

The solution ensures PoE is enabled with 'power inline auto' and sets the voice VLAN correctly. Verification with 'show interfaces switchport' should show 'Voice VLAN: 20' and 'show power inline' should show 'auto' for both ports.

Exam trap

Candidates often confuse the need for a trunk port when multiple VLANs are involved, but the voice VLAN feature allows an access port to carry both data and voice traffic. Also, remember that 'power inline auto' is the default but may need to be explicitly configured if disabled. Always verify with 'show interfaces switchport' to see the voice VLAN and 'show power inline' to see PoE status.

Why the other options are wrong

B

The specific factual error is that trunk ports are used to carry multiple VLANs between switches, not for connecting end devices like phones and PCs. The correct method is to use an access port with a voice VLAN.

C

The specific factual error is that 'power inline never' explicitly disables PoE, which would prevent the phone from powering on. The correct command is 'power inline auto' to enable PoE detection and delivery.

D

The specific factual error is that the VLAN numbers are reversed. The access VLAN should be the data VLAN (10), and the voice VLAN should be 20. Swapping them would place data traffic in VLAN 20 and voice in VLAN 10, which is not the intended configuration.

Why candidates pick the wrong answer

B

Candidates might think that because two VLANs are needed (voice and data), a trunk port is required. However, Cisco's voice VLAN feature allows both VLANs on an access port.

C

Candidates might confuse 'never' with 'auto' or think that PoE is enabled by default and doesn't need configuration. However, if the port shows 'off', it must be explicitly set to 'auto'.

D

Candidates might misread the question or confuse which VLAN is for voice and which for data. The question clearly states 'Voice VLAN 20, Data VLAN 10'.

1352
MCQeasy

Which data format is most commonly used in REST APIs because it is lightweight and easy for applications to parse?

A.YANG
B.JSON
C.STP
D.TFTP
AnswerB

JSON is the standard data-interchange format for REST APIs because it is lightweight, human-readable, and natively supported by JavaScript, making it trivial to parse in browsers and servers. It represents structured data as key-value pairs and arrays, mirroring the object literal syntax of many programming languages, and is transmitted with the Content-Type: application/json header. Its low overhead and easy mapping to language objects make it the default choice for most modern web APIs.

Why this answer

JSON is widely used with REST because it is compact, human-readable, and easy for software to parse. It is common in controller APIs and automation workflows.

Exam trap

A common exam trap is selecting YANG as the data format for REST APIs because candidates recognize YANG as related to network automation. However, YANG is a data modeling language that defines the structure of data but does not represent the actual data format used in REST API communication. Confusing YANG with JSON leads to incorrect answers.

Similarly, confusing protocols like STP or TFTP with data formats can mislead candidates. The key is to remember that JSON is the actual data format used in REST APIs due to its lightweight and easy-to-parse nature.

Why the other options are wrong

A

YANG is a data modeling language used to define the structure of network data but is not the actual data format used in REST API communication, making it an incorrect choice.

C

STP (Spanning Tree Protocol) is a Layer 2 protocol for preventing loops in Ethernet networks and has no relation to data formatting in REST APIs, so it is incorrect.

D

TFTP is a simple protocol used for file transfers, such as IOS images, and is not a data format used in REST APIs, making it an invalid choice.

When would these options actually be correct?

A

If the exam question asked for a data format used in network configuration protocols or data modeling languages, YANG would be the correct answer, as it is specifically designed for those purposes.

C

If the exam question asked about protocols used in network communications or data link layer technologies, STP could be the correct answer when discussing methods to manage network topology and prevent broadcast storms.

D

If the exam question asked about protocols used for transferring files in a network environment, TFTP could be the correct answer. For example, a question could specify which protocol is best suited for simple file transfers in a low-overhead scenario.

Why candidates pick the wrong answer

A

Candidates may confuse YANG with JSON due to their roles in data handling; they might recall YANG's relevance in network contexts and mistakenly associate it with REST API data formats.

C

Candidates may confuse STP with data formats due to its acronym and association with network technologies, leading them to mistakenly believe it could relate to data interchange in APIs.

D

Candidates might confuse TFTP with data formats due to its association with data transfer, leading them to mistakenly believe it relates to data interchange formats like JSON.

1353
MCQmedium

A switchport connected to an IP phone and a PC must carry user traffic and voice traffic separately. Which feature is designed for that purpose on a Cisco access port?

A.Voice VLAN
B.EtherChannel
C.SPAN
D.Native VLAN
AnswerA

A voice VLAN is the correct feature because it lets a single access switchport carry both an IP phone's 802.1Q-tagged voice frames and the PC's untagged data frames in the native/configured access VLAN. The phone is configured to tag its media with the Voice VLAN ID while leaving PC traffic untagged, enabling logical separation of voice and data on one physical port.

Why this answer

The correct feature is a voice VLAN. In plain language, a voice VLAN lets the switch treat the IP phone’s traffic differently from the user PC’s traffic even though both devices may be connected through the same physical access port. The phone can tag voice traffic for the voice VLAN while the PC remains in the normal data access VLAN. This is a practical design because it keeps voice traffic logically separate, which helps with policy, QoS, and management.

This is a classic CCNA switching concept because it shows that one physical edge port can still support more than one logical traffic type in a controlled way. A standard access VLAN by itself would not provide the same voice/data separation. EtherChannel, SPAN, and native VLAN concepts solve different problems. The best answer is the feature specifically built to support phones and workstations together on one access connection while keeping their traffic logically distinct.

Exam trap

Be cautious not to confuse VLAN-related terms. Understand that voice VLAN is specifically designed for separating voice and data traffic on access ports.

Why the other options are wrong

B

EtherChannel is a technology used to combine multiple physical links into a single logical link for increased bandwidth and redundancy, but it does not separate user and voice traffic on a switchport. Therefore, it does not fulfill the requirement of carrying voice and user traffic separately.

C

SPAN (Switched Port Analyzer) is used for monitoring and capturing traffic on a switch port, not for separating user and voice traffic. It does not provide the necessary functionality to handle VLANs for voice and data traffic on a single port.

D

The Native VLAN is used for untagged traffic on a trunk port and does not separate voice and user traffic on an access port. It is not designed to handle the specific requirements of carrying both voice and data traffic separately.

When would these options actually be correct?

B

If the exam question asked about increasing bandwidth for a connection between a switch and a server by aggregating multiple links, then EtherChannel would be the correct answer, as it allows for load balancing and redundancy across those links.

C

If the question were about monitoring traffic for troubleshooting purposes on a switch port, SPAN would be the correct answer. For example, a question might ask which feature allows an administrator to capture and analyze traffic from a specific port without affecting the normal operation of the network.

D

If the question asked about configuring a trunk port to carry multiple VLANs, including untagged traffic, the Native VLAN would be the correct answer. In that scenario, it would refer to the VLAN that carries untagged frames on a trunk link.

Why candidates pick the wrong answer

B

Candidates may choose EtherChannel because they associate it with improving network performance and may overlook the specific requirement of separating voice and user traffic, leading to confusion about the correct technology for the scenario presented.

C

Candidates may choose SPAN because they associate it with traffic management and monitoring, thinking it could help in separating or analyzing voice and data traffic, despite it not being the correct feature for VLAN separation.

D

Candidates may confuse the Native VLAN with the concept of VLANs in general, thinking it plays a role in traffic separation, especially if they are familiar with VLAN configurations but not the specific requirements for voice and data separation.

1354
MCQhard

Two routers, R1 and R2, are connected via a serial link. The interface on R1 shows 'Serial0/0 is up, line protocol is down' and no pings succeed across the link. You check the configuration and notice R1 has 'encapsulation ppp' but R2's serial interface was mistakenly left at the default encapsulation hdlc.

A.The IP addresses on the serial interfaces are in different subnets, so packets are dropped at Layer 3.
B.The mismatched encapsulation types prevent the routers from forming a Layer 2 connection, so the line protocol remains down.
C.The serial cable is faulty, causing physical layer issues that trigger the line protocol down state.
D.The routers are missing a routing protocol configuration, so they cannot route traffic across the link.
AnswerB

This is the correct diagnosis. The serial interfaces are configured with different encapsulations: one uses PPP and the other uses HDLC (or another incompatible type). Each encapsulation defines a distinct frame structure, and a router receiving a frame that does not match its configured format cannot interpret the contents or properly validate the keepalive messages. Consequently, the keepalive process fails, and the router marks the line protocol as 'down' even though the physical layer (carrier detect) remains active. This is a classic Layer 2 mismatch that prevents the routers from ever establishing a working data-link connection.

Why this answer

The line protocol on a serial interface requires both ends to agree on the Layer 2 encapsulation type. R1 is configured with PPP (encapsulation ppp), while R2 defaults to HDLC. Since these encapsulations are incompatible, the routers cannot establish a valid Layer 2 connection, causing the line protocol to remain down despite the physical layer being up.

Exam trap

Cisco often tests the distinction between 'line protocol is down' (Layer 2 issue) and 'Serial0/0 is down' (Layer 1 issue), and candidates mistakenly attribute a line protocol down state to physical problems or IP addressing errors rather than encapsulation mismatch.

Why the other options are wrong

A

The line protocol down state is a Layer 2 indicator, not a Layer 3 problem. It reflects the failure of the data link layer to establish a connection, independent of IP addressing.

C

The 'interface up' part of the status explicitly confirms that the physical layer (Layer 1) is operational. A faulty cable would cause both physical and line protocol to show down.

D

Line protocol down indicates a Layer 2 failure, which occurs before any routing decision. Even without a routing protocol, the line protocol would come up if Layer 2 were functional, because the interface status is independent of routing.

1355
MCQhard

R1 and R2 are directly connected via Ethernet on interface G0/0. Both interfaces are in the same subnet and configured for OSPF area 0. After enabling OSPF, R1's G0/0 is stuck in the INIT state in the OSPF neighbor table. What is the most likely cause?

A.MTU mismatch
B.Hello and dead timer mismatch
C.Missing router ID on both routers
D.A duplicate static route to 10.1.12.0/30
AnswerB

OSPF adjacency requires that Hello and Dead intervals match exactly between neighbors on the same link. The Dead interval is typically four times the Hello interval, but if one side is configured with different timers (e.g., 10/40 vs 30/120), the routers will discard each other's Hello packets and never reach the 2-Way state. This is the classic cause of a neighbor relationship that remains completely down, with no OSPF neighbor entry at all.

Why this answer

Being stuck in the INIT state means R1 has received Hello packets from R2 but has not transitioned to the 2-WAY state. This most often occurs when critical OSPF parameters like the hello and dead timers do not match. An MTU mismatch, while problematic, would cause the adjacency to fail during database exchange (Exstart/Exchange), not during initial neighbor formation.

Missing router IDs are not a real issue because routers auto-generate them, and a duplicate static route to the connected subnet would not affect OSPF neighbor discovery.

Exam trap

A common exam trap is selecting MTU mismatch or missing router IDs as the cause of OSPF adjacency failure. While MTU mismatches can cause adjacency issues during database exchange, they do not prevent the initial neighbor relationship from forming. Missing router IDs do not block adjacency because routers automatically generate IDs if none are configured.

Another trap is confusing static routes with neighbor discovery; static routes do not influence OSPF adjacency. The key is to focus on timer mismatches, as hello and dead intervals must be identical for routers to recognize each other as neighbors and establish adjacency.

Why the other options are wrong

A

MTU mismatch can cause OSPF adjacency problems during the database exchange phase, but it does not typically prevent the initial neighbor relationship from forming. Since the question states adjacency cannot form, MTU mismatch is unlikely the primary cause.

C

Missing router IDs do not prevent OSPF adjacency because routers automatically generate a router ID if none is configured. Therefore, this option is not a valid cause for adjacency failure.

D

A duplicate static route to 10.1.12.0/30 does not affect OSPF neighbor formation, as static routes are unrelated to OSPF adjacency processes. This option is irrelevant to the adjacency issue.

When would these options actually be correct?

A

In a different scenario where the question specifies that both routers are configured with different MTU sizes, and the OSPF packets exceed the smaller MTU, this option would be correct. For example, if R1 has an MTU of 1500 and R2 has an MTU of 1400, this could lead to adjacency issues.

C

In a different question, if the scenario described routers that were configured to use OSPF but had no router ID set, and the question asked why OSPF routes were not being advertised, then this option would be correct as it directly impacts OSPF operation.

D

In a scenario where the question specifies that R1 and R2 are using static routing instead of OSPF, and both routers have a duplicate static route configured for the same destination, this could lead to routing conflicts. The question would need to focus on static routing behavior rather than OSPF adjacency.

Why candidates pick the wrong answer

A

Candidates may choose this option because they associate MTU mismatches with connectivity issues in networking, leading them to believe it could be a plausible cause for OSPF adjacency failures.

C

Candidates may choose this option because they associate router IDs with OSPF functionality and believe that a missing router ID would inherently disrupt OSPF operations, leading to adjacency issues.

D

Candidates might choose this option because they associate routing issues with static routes and believe that any routing conflict could disrupt OSPF operations, even though this is not the case.

1356
Drag & Dropmedium

Drag and drop the following steps into the correct order to configure a Cisco switch access port with a data VLAN and a voice VLAN.

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

First, enter global configuration mode with 'configure terminal'. Next, select the interface using 'interface GigabitEthernet0/1'. Then, set the port to access mode with 'switchport mode access' to prevent trunk negotiation.

After that, assign the data VLAN with 'switchport access vlan 10'. Finally, assign the voice VLAN with 'switchport voice vlan 20'. This order ensures the interface is properly configured before VLAN assignment and prevents DTP from creating a trunk.

1357
Multi-Selectmedium

Which two statements accurately describe DHCP?

Select 2 answers
A.It can automatically provide an IP address to a client.
B.It can provide additional configuration such as default gateway and DNS server information.
C.It resolves hostnames into IP addresses.
D.It elects the designated router in OSPF.
E.It replaces the need for subnet masks.
AnswersA, B

This is correct because address assignment is a core DHCP function.

Why this answer

DHCP is used to provide IP configuration automatically to hosts. In practical terms, it can supply an IP address, subnet mask, default gateway, and often DNS server information. This reduces manual effort and helps standardize endpoint configuration across a network.

The wrong answers often confuse DHCP with DNS or routing. The two correct answers are the ones focused on automatic host configuration.

Exam trap

A common exam trap is confusing DHCP with DNS or routing protocol functions. Some candidates mistakenly believe DHCP resolves hostnames to IP addresses, but this is the role of DNS. Others incorrectly think DHCP participates in routing protocol processes such as OSPF designated router elections, which it does not.

Additionally, some may assume DHCP eliminates the need for subnet masks, but DHCP actually provides subnet mask information to clients. Recognizing that DHCP strictly handles IP address and related configuration assignment prevents these errors.

Why the other options are wrong

C

Incorrect. DHCP does not resolve hostnames to IP addresses; this is the responsibility of DNS, a separate IP service.

D

Incorrect. DHCP does not participate in routing protocol operations like OSPF designated router election, which is a function of OSPF itself.

E

Incorrect. DHCP supplies subnet masks to clients but does not replace the need for subnet masks; subnetting remains a fundamental network design concept.

When would these options actually be correct?

C

In a question asking which protocol is responsible for resolving hostnames to IP addresses, option C would be correct if the context specifically pertains to DNS operations. For example, a question could ask about the role of DNS in a network setup.

D

If the question were about OSPF functionality, specifically asking which protocol is responsible for electing the designated router, option D would be correct. In that context, a candidate might be asked to identify routing protocol behaviors, making this statement valid.

E

In a scenario where the exam question asks about protocols that eliminate the need for traditional networking configurations, such as in a highly abstracted cloud environment where subnetting is managed automatically, this option could be considered correct.

Why candidates pick the wrong answer

C

Candidates may choose this option due to a misunderstanding of network protocols, confusing DHCP's role in IP address assignment with DNS's role in hostname resolution, leading to an assumption that DHCP handles both functions.

D

Candidates might be tempted by option D due to a misunderstanding of network protocols, conflating DHCP's role in IP address management with OSPF's routing functions, leading them to incorrectly associate DHCP with router election processes.

E

Candidates may find this option tempting due to a misunderstanding of DHCP's role in network configuration, confusing its ability to manage IP addresses with the idea that it can eliminate the need for fundamental networking concepts like subnet masks.

1358
MCQmedium

As a general rule, where should an extended ACL be placed?

A.As close to the source as practical
B.As close to the destination as possible in all cases
C.Only on the default gateway
D.Only on WAN interfaces
AnswerA

Placing an extended ACL as close to the source as practical is the standard rule because extended ACLs can match both source and destination addresses, ports, and protocols. By filtering at the ingress point near the source, you prevent unwanted traffic from consuming bandwidth and processing resources on intermediate routers and links. This early filtering also reduces the risk of the traffic causing harm deeper inside the network, making the policy more efficient and effective.

Why this answer

Extended ACLs are commonly placed near the source to stop unwanted traffic earlier and conserve bandwidth and device resources.

Exam trap

Remember that extended ACLs should be placed near the source, not the destination or core, to effectively manage traffic.

Why the other options are wrong

B

Placing an extended ACL as close to the destination can lead to unnecessary traffic being processed by intermediate devices, which is inefficient. Extended ACLs are designed to filter traffic based on source and destination, so positioning them closer to the source enhances performance and security.

C

This option is incorrect because placing an extended ACL only on the default gateway limits its effectiveness in controlling traffic originating from various sources across the network. Extended ACLs should be strategically placed closer to the source to filter traffic before it reaches the destination.

D

Placing an extended ACL only on WAN interfaces can lead to inefficient traffic filtering, as it may not adequately control traffic originating from internal sources. Extended ACLs should ideally be positioned close to the source to effectively manage traffic before it reaches the destination.

When would these options actually be correct?

B

In a scenario where the question specifies that the network is highly segmented and traffic must be controlled at the destination for compliance reasons, placing an extended ACL close to the destination might be the best approach to enforce specific access policies for that segment.

C

In a scenario where a question specifies that all traffic must be filtered at the default gateway due to a specific network design or security policy, stating that extended ACLs should only be on the default gateway could be correct. For example, if the question indicates that the network is small and all traffic must pass through the gateway, this option would apply.

D

In a scenario where the exam question specifies that the network design requires strict control over traffic entering and leaving a WAN connection, placing an extended ACL only on WAN interfaces could be the correct answer. This would apply in a situation where all traffic must be filtered at the edge of the network for security compliance.

Why candidates pick the wrong answer

B

Candidates may choose this option because they associate ACLs with controlling access at the endpoint, believing that filtering at the destination is a more secure practice without considering the efficiency of traffic management.

C

Candidates may choose this option due to a misunderstanding of ACL placement principles, believing that centralizing control at the default gateway simplifies management and security, without considering the broader implications of traffic flow.

D

Candidates may find this option tempting because they associate WAN interfaces with external traffic control, leading them to believe that filtering at this point is sufficient for managing network security.

1359
MCQhard

A router has a static route configured: ip route 10.200.0.0 255.255.0.0 GigabitEthernet0/1. The output of show ip interface brief shows that interface GigabitEthernet0/1 is administratively down. Why is the route to 10.200.0.0/16 present in the running configuration but absent from the routing table?

A.Because the route points to an interface that is administratively down.
B.Because static routes cannot reference exit interfaces.
C.Because the destination must be a /24, not a /16.
D.Because static routes require NTP before installation.
AnswerA

A static route that specifies only an exit interface is installed in the routing table only when that interface is in an up/up state. An administratively down interface (shutdown) makes the route invalid because the router cannot use that path for packet forwarding, even though the configuration exists. Therefore the route is absent from the show ip route output and no traffic is sent to 10.200.0.0/16.

Why this answer

The static route is absent because the outgoing interface is down. In practical terms, when a static route depends on an interface that is not operational, the router cannot use that path, so the route is not installed as usable forwarding state. The configuration line alone is not enough; the forwarding path also has to be viable.

This is a realistic static-route troubleshooting pattern because it distinguishes between configured intent and operational state.

Exam trap

A frequent exam trap is to confuse the presence of a static route in the configuration with its presence in the routing table. Candidates often overlook the fact that a static route pointing to an administratively down interface will not be installed, leading to the mistaken belief that the route is missing due to mask length or protocol requirements. Another trap is assuming static routes cannot use exit interfaces or require time synchronization, which is false.

This question tests the candidate's understanding of the difference between configured routes and operationally valid routes, focusing on interface state as the critical factor for route installation.

Why the other options are wrong

B

Incorrect because static routes can reference exit interfaces directly; Cisco routers support static routes with either next-hop IP addresses or exit interfaces.

C

Incorrect because the subnet mask length (such as /16 vs /24) does not prevent a static route from being installed; the issue is the interface state, not the mask.

D

Incorrect because static routes do not depend on NTP or time synchronization for installation; this is unrelated to static routing behavior.

When would these options actually be correct?

B

In a different scenario, if a question asked about a router configuration where static routes were incorrectly set up to reference non-existent or misconfigured interfaces, then this option could be correct. For example, if the question specified that the static route was configured to point to an interface that does not exist, it would validate this option.

C

In a different question setup, if the question specified that static routes were only allowed for /24 networks due to specific router limitations or configurations, then this option would be correct. For example, a question could state that the router only supports /24 static routes for routing to specific subnets.

D

In a different scenario, if a question stated that a static route was not being installed because the router was unable to synchronize its clock with an NTP server, then this option would be correct. For example, if the question involved time-sensitive routing protocols that depend on accurate timestamps.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of static route configurations, believing that there are restrictions on referencing interfaces, especially if they have encountered scenarios where misconfigurations led to routing issues.

C

Candidates may choose this option due to a misunderstanding of subnetting rules and the belief that static routes are restricted to certain subnet masks, leading them to incorrectly assume that a /16 is invalid.

D

Candidates may be tempted by this option due to a misunderstanding of the requirements for static routes and the role of NTP in network configurations, leading them to incorrectly associate time synchronization with routing issues.

1360
MCQhard

A network engineer is troubleshooting OSPFv3 adjacency between two directly connected Cisco routers, R1 and R2, both running IOS-XE. The engineer configures OSPFv3 on both routers but notices that the adjacency does not form. The engineer runs 'show ospfv3 neighbor' on R1 and sees no neighbors. What is the most likely cause of this issue?

A.The OSPFv3 process ID must match on both routers.
B.The interface GigabitEthernet0/0 is missing the 'ospfv3 1 ipv6 area 0' command.
C.The link-local addresses are not in the same subnet.
D.The router ID 1.1.1.1 is duplicated on R2.
AnswerB

With OSPFv3, enabling the OSPF process globally is not enough; each participating interface must be explicitly activated with the 'ospfv3 1 ipv6 area 0' interface-level configuration. This command assigns the interface to the OSPFv3 process 1 for address family IPv6 and places it into area 0. Without this command, the router will not send or listen for OSPFv3 Hello messages on GigabitEthernet0/0, so no neighbor adjacency can ever form. That is exactly why R2's neighbor entry is missing from the 'show ospfv3 neighbor' output.

Why this answer

OSPFv3 requires explicit interface-level configuration to enable the protocol on a specific interface. The correct command is 'ospfv3 1 ipv6 area 0' (or 'ipv6 ospf 1 area 0' for the traditional OSPFv3 configuration). Without this command, the interface does not participate in OSPFv3, so no Hello packets are sent or received, preventing adjacency formation.

Exam trap

Cisco often tests the distinction between OSPFv2 (where enabling the protocol under the routing process automatically activates it on all interfaces with 'network' statements) and OSPFv3 (which requires explicit per-interface activation), leading candidates to overlook the mandatory interface-level command.

Why the other options are wrong

A

This is a common misconception; OSPFv3 uses the router ID for neighbor identification, not the process ID.

C

Link-local addresses are automatically configured and do not affect OSPFv3 adjacency as long as they are unique.

D

In this scenario, no neighbors are seen, indicating a more fundamental issue like OSPFv3 not being enabled on the interface.

1361
PBQmedium

You are connected to R1, a Cisco IOS-XE router that provides connectivity for the 192.168.10.0/24 network. The network operations team uses a Python script with netmiko to push configuration changes. However, the script fails to connect to R1. You need to verify the SSH configuration on R1.

Hints

  • Check if SSH is enabled globally and on the VTY lines.
  • Verify that the transport input includes ssh.
  • Ensure there is a hostname and domain configured.
A.The VTY lines are configured for telnet only; SSH requires 'transport input ssh'.
B.The SSH server is not enabled because the crypto key is missing or 'ip ssh' is not configured.
C.The SSH version is set to version 1, which is not supported by the Python script.
D.The domain name is not configured, which is required for SSH key generation.
AnswerA
solution
! R1
show running-config | include ssh
show ip ssh
show line vty
show ip interface brief

Why this answer

The VTY lines are configured for telnet only. SSH requires 'transport input ssh' (or 'transport input all'). Additionally, the SSH server may not be enabled if the crypto key is missing or the ip ssh command is not present.

The commands show that transport input is telnet, so the script cannot connect via SSH. Changing to 'transport input ssh' resolves the issue.

Exam trap

The exam trap is that candidates often focus on SSH server configuration (crypto keys, domain name, ip ssh) and forget that the VTY lines must also permit SSH. Always check 'transport input' on VTY lines when troubleshooting SSH access.

Why the other options are wrong

B

The specific factual error: The crypto key and 'ip ssh' are necessary for SSH operation, but the VTY transport setting is the immediate cause of connection failure.

C

The specific factual error: There is no indication that SSH version 1 is in use; the issue is the VTY transport setting.

D

The specific factual error: A domain name is required for SSH key generation, but the VTY transport setting is the direct cause of the connection failure.

Why candidates pick the wrong answer

B

Candidates pick this because they know SSH requires crypto keys and the 'ip ssh' command, but overlook that the VTY lines must also accept SSH.

C

Candidates pick this because they know SSH version 1 is outdated and may cause compatibility issues, but it is not the most likely cause here.

D

Candidates pick this because they recall that SSH setup requires a domain name and RSA keys, but they overlook the VTY line configuration.

1362
Multi-Selectmedium

A route table shows both a default route and a more specific route to 192.168.50.0/24. Which two statements describe how packets destined for 192.168.50.25 are handled?

Select 2 answers
A.The router prefers the 192.168.50.0/24 route because it is the longest prefix match
B.The default route is used only when no more-specific route matches
C.Administrative distance is compared before prefix length for forwarding decisions
D.The packet is load-balanced across both routes automatically
AnswersA, B

The 192.168.50.0/24 route wins because longest prefix match dictates that the most specific route among all matching entries is used. With a /24 mask, it matches a narrower address range than the /0 default route, making it the superior entry for any destination inside 192.168.50.0/24. Forwarding therefore uses that route's next hop directly.

Why this answer

Once routes are installed, packet forwarding follows longest prefix match. The /24 route is more specific than the default route, so traffic to 192.168.50.25 uses the /24 entry.

Exam trap

A frequent exam trap is assuming that administrative distance is compared before prefix length when selecting a route. Candidates might think that if the default route has a better administrative distance, it will be chosen over a more specific route. However, Cisco routers always apply the longest prefix match rule first, selecting the most specific route regardless of administrative distance.

Administrative distance only comes into play when multiple routes have the same prefix length. Misunderstanding this can lead to incorrect answers about how packets are forwarded, especially when both default and specific routes exist in the routing table.

Why the other options are wrong

C

Option C is incorrect because administrative distance is not compared before prefix length; prefix length is the primary factor in route selection, making this option a common misconception.

D

Option D is incorrect because Cisco routers do not load-balance between a default route and a more specific route; these routes are not considered equal-cost and the more specific route is always preferred.

When would these options actually be correct?

C

This option would be correct in a question where two routes to the exact same destination network (e.g., both 192.168.50.0/24) exist from different routing protocols (e.g., OSPF and static), and the router must choose which route to install in the routing table based on administrative distance.

D

If the question stated that both routes have equal prefix length (e.g., both are /24) and equal administrative distance/metric, then the router would load-balance traffic across them using per-packet or per-destination load balancing.

Why candidates pick the wrong answer

C

Candidates often confuse the order of route selection criteria, mistakenly thinking administrative distance is compared before prefix length, especially when they recall that AD is used to choose between routes but forget that prefix length is evaluated first.

D

Candidates may confuse ECMP (equal-cost multipath) load balancing with the behavior of routes of different prefix lengths, assuming the router distributes traffic across all available routes.

1363
MCQhard

A router is configured for PAT using the WAN interface address. Which command element is most directly associated with allowing many internal users to share that single outside address?

A.overload
B.inside
C.list 1
D.interface
AnswerA

The `overload` keyword is the essential PAT enabler in an `ip nat inside source list ... interface ... overload` command. Without it, the router performs only dynamic NAT, mapping one inside local address to one inside global address at a time. Overload forces the router to reuse the single WAN interface IP address by multiplexing sessions through unique transport-layer port numbers, supporting many inside hosts simultaneously. This keyword directly translates to Port Address Translation, making it the correct answer.

Why this answer

The `overload` element is the critical part. In plain language, that keyword tells the router to perform Port Address Translation so many inside sessions can be represented through the same outside IP address at the same time. Without overload, the router would be performing a different translation behavior and would not achieve the same many-to-one sharing model.

This is one of the most recognizable NAT design terms in CCNA because it directly distinguishes PAT from simple one-to-one translation methods. The correct answer is the part of the configuration that signals multi-session sharing through port tracking.

Exam trap

A common exam trap is selecting options like `inside`, `list 1`, or `interface` as the element that enables multiple internal users to share a single outside address. While these elements are part of the NAT configuration, they do not by themselves enable PAT. The `inside` keyword only marks interfaces as internal, the ACL (`list 1`) defines which addresses are translated, and specifying the `interface` chooses the public IP address source.

However, without the `overload` keyword, the router cannot perform port-based multiplexing, so many-to-one sharing fails. Candidates often overlook that `overload` is the explicit command that activates PAT, making it the correct answer.

Why the other options are wrong

B

Incorrect. The `inside` keyword only marks an interface as internal for NAT direction but does not enable multiple hosts to share one outside address.

C

Incorrect. The access list (`list 1`) specifies which internal addresses are translated but does not activate PAT or many-to-one sharing by itself.

D

Incorrect. Specifying the interface determines the outside IP address used for translation but does not enable PAT without the `overload` keyword.

When would these options actually be correct?

B

In a different question asking about identifying the internal network designation in a NAT configuration, the option 'inside' would be correct when the question specifies which command element defines the internal IP address range used for NAT translations.

C

In a different question that asks about the purpose of access lists in NAT configurations, 'list 1' could be the correct answer if the question specifies that it is used to permit or deny specific internal addresses from being translated to the outside address.

D

In a different question, if it asked about the command used to specify which interface to apply PAT on, 'interface' would be correct. For example, a question could ask, 'Which command element is used to define the external interface for NAT?'

Why candidates pick the wrong answer

B

Candidates may confuse the term 'inside' with the concept of internal users, leading them to believe it plays a crucial role in the context of sharing an external address, despite its actual function being more about defining the internal network.

C

Candidates may choose 'list 1' because they associate access lists with NAT configurations and believe that controlling which addresses can be translated is directly related to sharing an outside address.

D

Candidates may choose 'interface' because they associate it with the configuration of NAT and might mistakenly believe it directly relates to the functionality of allowing multiple users to share an address, overlooking the specific role of 'overload' in this context.

1364
MCQhard

A technician is troubleshooting a connectivity issue where a workstation connected to a Cisco switch port cannot ping other hosts that are in the same VLAN 10 segment. The technician runs the show mac address-table command and notices that the workstation's MAC address is listed on VLAN 1, not VLAN 10. What is the most likely cause?

A.The switch port is not configured with the switchport access vlan 10 command.
B.The switch port is configured as a trunk with native VLAN 1.
C.The MAC address table contains a stale entry that must be cleared.
D.Spanning Tree Protocol has placed the port in a blocking state.
AnswerA

When an access port's VLAN is not explicitly set, the port defaults to VLAN 1. The workstation's MAC is learned on VLAN 1, causing connectivity failure with VLAN 10 hosts. Adding the switchport access vlan 10 command resolves the issue.

Why this answer

The workstation's MAC address appears in VLAN 1 instead of VLAN 10 because the switch port is operating in the default VLAN (VLAN 1). The most likely cause is that the port has not been explicitly assigned to VLAN 10 using the `switchport access vlan 10` command. Without this command, the port remains in its default access VLAN (VLAN 1), so all frames from the workstation are associated with VLAN 1, preventing communication with hosts in VLAN 10.

Exam trap

Cisco often tests the default VLAN behavior (VLAN 1) and the fact that an access port without an explicit VLAN assignment remains in VLAN 1, leading candidates to overlook the missing `switchport access vlan` command and instead blame trunking, STP, or MAC table aging.

Why the other options are wrong

B

Candidates often assume any VLAN mismatch with VLAN 1 indicates a trunk misconfiguration, but a missing access VLAN is the more common and direct cause.

C

Candidates might think that an outdated MAC record is causing the VLAN display, but the dynamic learning process reflects the actual port VLAN.

D

Tempting because a blocked port can disrupt connectivity, but the MAC address table entry would still appear on the correct VLAN, not default to VLAN 1.

1365
Multi-Selectmedium

Which TWO statements about interpreting routing table output are true? (Choose two.)

Select 2 answers
A.A route with a longer prefix length is always preferred over a route with a shorter prefix length, regardless of administrative distance.
B.A directly connected route has an administrative distance of 0 and is always preferred over any dynamic route for the same network.
C.If two routes have the same prefix length, the route with the higher administrative distance is preferred.
D.The metric is used to compare routes from different routing protocols.
E.A static route configured with an administrative distance of 200 will be preferred over an OSPF route with AD 110 for the same network.
AnswersA, B

The longest-prefix match rule is the first criterion in the routing table lookup: a route with a longer subnet mask (e.g., /32) is always selected over a less specific route (e.g., /24) for the same destination, even if that less specific route has a much lower administrative distance. Administrative distance becomes relevant only after the router identifies the set of routes with the longest matching prefix length. For example, a static route to 10.0.0.0/24 with AD 1 will lose to an OSPF route to 10.0.0.0/32 with AD 110, because specificity determines the winning route before AD is ever considered.

Why this answer

Longest-prefix match always wins regardless of AD or route source (A correct), and directly connected routes have AD 0 (B correct). C is incorrect because among equal prefix lengths, lower AD wins. D is wrong because metric only compares same-protocol routes, while AD compares across protocols.

E fails because a higher AD (200) is less preferred than OSPF's 110.

Exam trap

Cisco often tests the misconception that administrative distance is the primary tie-breaker, but the trap here is that the longest prefix match rule always takes precedence, even over a directly connected route with AD 0.

Why the other options are wrong

C

A lower AD indicates a more trustworthy source, so the route with the lower AD is preferred, not the higher one.

D

Metrics are only comparable within the same routing protocol (e.g., OSPF cost vs. EIGRP composite metric). For different protocols, AD is used to select the best route.

E

A lower AD is preferred; OSPF AD 110 is lower than 200, so the OSPF route would be chosen.

1366
MCQhard

Exhibit: Users report no internet access after PAT was configured. The inside and outside interfaces are marked correctly. Which missing configuration is the most likely cause?

A.No ACL and nat overload statement identifying inside source addresses
B.No DHCP pool on the outside interface
C.No CDP enabled on the router
D.No syslog server configured
AnswerA

For PAT to be operational, the router must have an access list that identifies the inside local source addresses to be translated, along with an ip nat inside source list <ACL> interface <outside> overload statement that actually enables port address translation. Without this ACL and overload rule, the router has no dynamic translation entry, so private inside addresses are forwarded untranslated to the ISP and the return traffic cannot be routed back. This missing configuration directly causes the intermittent or complete loss of internet access, making it the correct root cause.

Why this answer

PAT needs both the inside and outside interface roles and a NAT statement referencing an ACL that identifies the inside local addresses. Without the ACL match and NAT overload rule, translation does not occur for user traffic.

Exam trap

A frequent exam trap is believing that configuring the inside and outside interfaces alone is enough for PAT to function correctly. Candidates may overlook the necessity of an ACL that explicitly identifies the inside local addresses for translation. Without this ACL and the corresponding NAT overload statement, the router cannot perform address translation, causing intermittent or failed internet connectivity.

This mistake often occurs because the interface roles are visible and seem sufficient, but the translation logic depends on the ACL match. Understanding that PAT requires both interface roles and an ACL-based NAT overload rule is critical to avoid this pitfall.

Why the other options are wrong

B

Incorrect. DHCP pools assign IP addresses to clients and are unrelated to NAT or PAT configuration. Lack of a DHCP pool on the outside interface does not affect PAT functionality.

C

Incorrect. CDP is a Layer 2 protocol used for device discovery and does not influence NAT or PAT operations. Its absence does not cause internet access issues related to PAT.

D

Incorrect. Syslog servers are used for logging and monitoring router events. Not configuring a syslog server does not impact NAT translation or internet connectivity.

When would these options actually be correct?

B

In a different scenario where the question specifies that users are trying to connect to the internet but are not receiving IP addresses, and the router's outside interface is expected to assign IP addresses dynamically, the absence of a DHCP pool would indeed be the correct answer.

C

In a question focused on network topology discovery, where the scenario involves troubleshooting connectivity issues between Cisco devices, the absence of CDP could be identified as the cause of the problem. For example, if the question asked about issues with device visibility or neighbor discovery, then not having CDP enabled would be the correct answer.

D

In a different scenario where a question focuses on network troubleshooting and monitoring, a candidate might be asked about missing configurations that affect logging and alerting. If the question specifies that logs are needed for troubleshooting connectivity issues, then not having a syslog server could be the correct answer.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of NAT and DHCP roles, thinking that DHCP is necessary for any internet access configuration, leading to confusion about their specific functions.

C

Candidates may confuse the importance of CDP in network management with its relevance to NAT configurations, leading them to mistakenly believe that it could affect internet access.

D

Candidates may choose this option because they understand the importance of logging in network management and might mistakenly believe that logging issues could lead to connectivity problems, thus overlooking the specific NAT-related context of the question.

1367
Drag & Dropmedium

Drag and drop the following steps into the correct order to configure and apply an extended IPv4 ACL on a Cisco router to block Telnet traffic from subnet 192.168.1.0/24 to host 10.0.0.1 and permit all other IP traffic.

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
6Step 6
7Step 7

Why this order

Correct order: 1) Identify the traffic to filter and the interface/direction because this planning determines all subsequent configuration choices. 2) Enter global configuration mode to access ACL definition. 3) Configure the deny statement first — ACLs are processed top-down, so the specific deny must precede the general permit to actually block the unwanted traffic. 4) Add the permit statement after the deny to allow everything else. 5) Enter interface configuration mode to attach the ACL to a specific port. 6) Apply the ACL with the correct direction (inbound) using the ip access-group command, which activates the filtering. 7) Verify the ACL is correctly applied to confirm the configuration is functioning as intended.

1368
MCQhard

A company wants internal users to share one public IPv4 address for outbound Internet access, while keeping sessions separate. Which NAT approach best meets that requirement?

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

PAT overload is the correct method because Port Address Translation (PAT) overload multiplexes thousands of internal private IP addresses through a single public IPv4 address by assigning each session a unique TCP or UDP port number. The router maintains a translation table that maps each internal IP:port combination to the public IP:port, allowing many internal users to share one public IPv4 address simultaneously. This is the standard many-to-one NAT approach used in home and enterprise edge routers.

Why this answer

PAT is the correct approach because it allows many internal sessions to share one outside IPv4 address while distinguishing them by port numbers. In plain language, PAT gives the office an efficient many-to-one translation model that works well for ordinary user Internet access when public addresses are limited.

This is different from static NAT, which gives a fixed one-to-one mapping, and from dynamic NAT pools that usually rely on multiple public addresses. The correct answer is the translation method designed specifically for shared public-address use across many sessions.

Exam trap

A common exam trap is selecting static NAT as the solution because it involves address translation, but static NAT only supports one-to-one mappings and cannot handle multiple internal users sharing a single public IP address. Another frequent mistake is assuming private IPv4 addresses can be routed on the Internet without NAT, which is incorrect because private addresses are non-routable externally. Additionally, confusing DHCP relay with NAT functions can mislead candidates, as DHCP relay only forwards DHCP messages and does not perform address translation.

Recognizing that PAT overload uniquely enables many-to-one translation with port differentiation is crucial to avoid these pitfalls.

Why the other options are wrong

B

Static NAT only provides a one-to-one mapping between private and public IP addresses, so it cannot support multiple internal users sharing one public IP address simultaneously, making it unsuitable for the scenario.

C

No NAT is incorrect because private IPv4 addresses are not routable on the public Internet; without NAT, internal users cannot access external resources using private IPs alone.

D

DHCP relay is unrelated to NAT or IP address translation; it simply forwards DHCP requests between clients and servers and does not enable sharing of public IP addresses for Internet access.

When would these options actually be correct?

B

In a scenario where a company has a specific requirement to map a single internal server's private IP address to a public IP for hosting a web service, a question might ask for the best NAT approach for that server's fixed IP address. In this case, Static NAT would be the correct choice.

C

In a scenario where a question states that a company is using a private network with a VPN that provides secure access to external resources, and the question asks about the feasibility of direct Internet access, 'No NAT' could be correct if the focus is on the VPN's ability to handle routing without NAT.

D

If the question asked about a scenario where a company needs to manage DHCP requests from multiple subnets without a local DHCP server, then DHCP relay would be the correct answer. This would involve ensuring that clients can obtain IP addresses from a centralized DHCP server located on a different network segment.

Why candidates pick the wrong answer

B

Candidates may choose this option because they recall that Static NAT is used for IP address mapping, leading them to mistakenly believe it could fulfill the requirement of sharing a public IP for multiple users.

C

Candidates may choose this option due to a misunderstanding of private IP address functionality, believing that private addresses can directly access the Internet without NAT, especially if they recall that private addresses are used in local networks.

D

Candidates may choose this option due to a misunderstanding of DHCP's role in network management, confusing it with NAT functionality, especially in scenarios involving multiple network segments.

1369
MCQmedium

Exhibit: A host on VLAN 10 can ping the local SVI but not a server in VLAN 20. The Layer 3 switch has both VLAN interfaces up. What is the next item to verify first?

A.Whether the server in VLAN 20 has the correct default gateway
B.Whether the switch should disable IP routing
C.Whether VLAN 10 should be the native VLAN
D.Whether the host should use a /8 mask instead of /24
AnswerA

The most likely fault is that the server in VLAN 20 lacks a properly configured default gateway (or has a gateway that points to a different router/switch). When the VLAN 10 host pings the server, the ICMP echo request is routed by the switch's SVI to VLAN 20, but if the server cannot send the echo reply back through the correct next hop, the ping fails. This creates a one-way reachability issue that is a classic symptom of an end-host gateway misconfiguration, not a problem with the switch's routing table or trunking.

Why this answer

If the source host can reach its own default gateway, the local VLAN and access port are probably fine. The next practical check is whether the server in VLAN 20 has the correct IP address, mask, and default gateway configured.

Exam trap

A frequent exam trap is to overlook the remote device’s default gateway configuration and instead suspect the Layer 3 switch’s routing or VLAN setup. Candidates often assume that because the VLAN interfaces are up, routing must be functional. However, if the server in VLAN 20 lacks the correct default gateway pointing to its VLAN SVI, it cannot return traffic to the source host, causing failed pings.

This one-way communication failure can mislead candidates into troubleshooting switch settings unnecessarily, wasting time and missing the root cause.

Why the other options are wrong

B

Disabling IP routing on the Layer 3 switch would prevent inter-VLAN routing entirely. Since both VLAN interfaces are up and the host can ping its local SVI, IP routing is likely enabled, so this is not the first item to verify.

C

The native VLAN setting affects untagged traffic on trunk links but does not directly impact inter-VLAN routing or the ability of hosts to communicate across VLANs. It is not the primary cause of the described symptom.

D

Using a /8 mask instead of /24 would cause subnetting issues, but since the host can ping its own VLAN interface, the subnet mask is likely correct. This is not the first or most probable cause of the problem.

When would these options actually be correct?

B

If the question described a scenario where the switch is acting as a Layer 2 switch and inter-VLAN routing is not required (e.g., all hosts in the same subnet), then disabling IP routing would be correct to prevent unintended routing behavior.

C

This option would be correct if the question described a scenario where a host in VLAN 10 cannot communicate with a host in VLAN 20 across a trunk link, and the switch ports are configured with mismatched native VLANs, causing untagged frames to be dropped or misdelivered.

D

If the host could not ping the local SVI and the question described connectivity issues to any destination, verifying the subnet mask (e.g., /8 vs /24) would be appropriate to rule out misconfiguration.

Why candidates pick the wrong answer

B

Candidates may think that disabling IP routing is a quick fix for connectivity issues without understanding that the SVI ping success proves routing is working locally, and the real problem is likely a missing or incorrect default gateway on the server.

C

Candidates may confuse native VLAN configuration with inter-VLAN routing, thinking that setting the correct native VLAN is necessary for Layer 3 communication between VLANs, especially when trunk ports are involved.

D

Candidates may confuse a host's inability to reach a remote subnet with a subnet mask mismatch, assuming the mask is too restrictive for routing.

1370
PBQhard

You are connected to R1 via the console. SNMP v2c community strings (public RO, private RW) are already configured. The network has a management server at 10.1.1.100 and a NetFlow collector at 10.1.1.200. Configure SNMP traps to the management server for link status changes. Also configure NetFlow on interface GigabitEthernet0/0 to export version 9 to the collector, with a source interface of Loopback0 (10.255.255.1/32).

Network Topology
G0/0G0/010.1.1.10010.1.1.200R210.0.0.1/30R1MGMT_ServerNMS_Collector

Hints

  • SNMP traps require both a host command and enabling specific trap types.
  • NetFlow export needs destination, version, and source interface, plus flow ingress on the interface.
  • Use 'show running-config | section snmp|flow' to verify your changes.
A.snmp-server host 10.1.1.100 version 2c public snmp-server enable traps snmp linkdown linkup ip flow-export destination 10.1.1.200 2055 ip flow-export version 9 ip flow-export source Loopback0 interface GigabitEthernet0/0 ip flow ingress
B.snmp-server host 10.1.1.200 version 2c private snmp-server enable traps ip flow-export destination 10.1.1.100 2055 version 9 ip flow-export source Loopback0 interface GigabitEthernet0/0 ip flow egress
C.snmp-server host 10.1.1.100 version 2c private snmp-server enable traps ip flow-export destination 10.1.1.200 2055 version 9 ip flow-export source Loopback0 interface GigabitEthernet0/0 ip flow ingress
D.snmp-server host 10.1.1.100 version 2c public snmp-server enable traps snmp linkdown linkup ip flow-export destination 10.1.1.200 2055 version 5 ip flow-export source Loopback0 interface GigabitEthernet0/0 ip flow ingress
AnswerA
solution
! R1
snmp-server host 10.1.1.100 version 2c public
snmp-server enable traps snmp linkdown linkup
ip flow-export destination 10.1.1.200 2055
ip flow-export version 9
ip flow-export source Loopback0
interface GigabitEthernet0/0
ip flow ingress

Why this answer

The current configuration has SNMP community strings but lacks trap destinations and NetFlow export. To fix, you must configure snmp-server host 10.1.1.100 version 2c public to send traps, and snmp-server enable traps snmp linkdown linkup is required to send link status changes. For NetFlow, you need ip flow-export destination 10.1.1.200 2055 and then ip flow-export version 9 to set the export version.

Also configure ip flow-export source Loopback0 and apply ip flow ingress on GigabitEthernet0/0. Verification commands confirm the settings.

Exam trap

Pay close attention to the IP addresses: the management server (10.1.1.100) is for SNMP traps, and the collector (10.1.1.200) is for NetFlow. Also, remember that SNMP traps use the read-only community, and NetFlow version must match the requirement (version 9).

Why the other options are wrong

B

The specific factual error: The SNMP trap destination and NetFlow export destination are swapped, and the flow direction is egress instead of ingress.

C

The specific factual error: SNMP traps should use the read-only community string 'public', not the read-write 'private'.

D

The specific factual error: NetFlow export version is set to 5, but the requirement is version 9.

Why candidates pick the wrong answer

B

Candidates might confuse the management server and collector IPs, or think that NetFlow egress is equivalent to ingress.

C

Candidates may think any community string works for traps, or they may confuse the roles of read-only and read-write communities.

D

Candidates might default to version 5 as it is older and commonly used, or they may not read the requirement carefully.

1371
MCQhard

A host address is 10.10.10.14/29. Which address is the broadcast address for its subnet?

A.10.10.10.7
B.10.10.10.15
C.10.10.10.8
D.10.10.10.16
AnswerB

The /29 CIDR notation specifies that the first 29 bits define the network portion, leaving 3 bits for host addresses. For the 10.10.10.14/29 subnet, the network address is 10.10.10.8. The broadcast address is always the last address within a subnet, derived by setting all host bits to one. In this scenario, setting the three host bits of the 10.10.10.8 network to one results in 10.10.10.15, which functions as the broadcast address for this specific subnet, satisfying the constraint of the /29 mask.

Why this answer

A /29 subnet has a block size of 8. In practical terms, the fourth-octet ranges are 0–7, 8–15, 16–23, and so on. Since 14 falls in the 8–15 block, the broadcast address is the last address in that block, which is 10.10.10.15.

This is a classic subnetting question that checks whether you can find the block first and then identify the final address in that block.

Exam trap

Avoid confusing the network address or a host address with the broadcast address. Remember, the broadcast address is the last address in the subnet range.

Why the other options are wrong

A

Option A, 10.10.10.7, is incorrect because it does not represent the broadcast address for the subnet defined by 10.10.10.14/29. The correct broadcast address is 10.10.10.15, which is the highest address in the subnet range.

C

The address 10.10.10.8 is not the broadcast address for the subnet 10.10.10.14/29. The correct broadcast address is 10.10.10.15, which is the highest address in the subnet range from 10.10.10.8 to 10.10.10.15.

D

The address 10.10.10.16 is outside the subnet defined by 10.10.10.14/29, which includes addresses from 10.10.10.8 to 10.10.10.15. Therefore, it cannot be the broadcast address for this subnet.

When would these options actually be correct?

A

In a different question, if the subnet mask were /28 and the host address were 10.10.10.0, then 10.10.10.7 could be the broadcast address for a subnet that includes 10.10.10.0/28, where the valid host range is 10.10.10.1 to 10.10.10.14.

C

If the question asked for the network address of the subnet that includes 10.10.10.14/29, then 10.10.10.8 would be the correct answer, as it represents the first address in that subnet range.

D

If the question specified a different subnet, such as 10.10.10.16/29, then 10.10.10.16 would be the broadcast address for that subnet. This would change the range of valid addresses and make D the correct answer.

Why candidates pick the wrong answer

A

Candidates may choose option A because they might misinterpret the subnetting rules and mistakenly calculate the broadcast address based on an incorrect understanding of subnet ranges.

C

Candidates may choose this option due to confusion between the concepts of broadcast and network addresses, mistakenly associating the address with a common subnet boundary.

D

Candidates might confuse the subnetting boundaries and mistakenly think that 10.10.10.16 could be a valid broadcast address due to its proximity to the range of addresses in the original subnet.

1372
Multi-Selectmedium

A switch should learn one MAC address on an access port and shut the port down if a second unauthorized device appears. Which two port-security settings support that requirement?

Select 2 answers
A.switchport port-security maximum 1
B.switchport port-security violation shutdown
C.switchport protected
D.switchport nonegotiate
AnswersA, B

The 'switchport port-security maximum 1' command under interface configuration enables port security and caps the number of learned secure MAC addresses to exactly one. Once a single device's MAC address is dynamically learned and stored in the secure MAC table, any additional source MAC address seen on the port is treated as a violation, triggering the configured violation action. This is the precise command needed to satisfy the requirement of learning only one MAC address, as it directly enforces the numerical limit on secure MAC entries.

Why this answer

Port security enforces how many MAC addresses may be learned on a port and what happens when a violation occurs. 'switchport port-security maximum 1' limits the port to one MAC address, and 'switchport port-security violation shutdown' disables the port if a violation occurs, matching the requirement. 'switchport protected' isolates ports within a switch but does not limit MAC addresses or cause a shutdown. 'switchport nonegotiate' disables DTP negotiation, which is unrelated to port security.

Exam trap

Be careful not to confuse the different port security violation modes. Only the shutdown mode will disable the port.

Why the other options are wrong

C

The 'switchport protected' command is used to isolate ports within a VLAN (private VLAN edge), preventing communication between protected ports. It does not limit MAC addresses or trigger port shutdown upon violation.

D

The 'switchport nonegotiate' command disables Dynamic Trunking Protocol (DTP) negotiation, preventing the port from becoming a trunk. It does not limit MAC addresses or enforce violation actions, so it cannot meet the requirement to learn one MAC and shut down on a second unauthorized device.

When would these options actually be correct?

C

This option would be correct in a question asking: 'Which command prevents traffic from being forwarded between ports in the same VLAN on a switch?' where the goal is to enforce port-level isolation for security.

D

This command is correct when the question asks to prevent a switch port from automatically forming a trunk with a connected device, such as when you want to ensure an access port remains an access port and avoid trunk misconfiguration.

Why candidates pick the wrong answer

C

Candidates may confuse 'protected' with 'port security' because both terms relate to security features, leading them to think it limits MAC addresses or enforces violations.

D

Candidates may confuse 'nonegotiate' with security features, thinking it prevents unauthorized devices by stopping negotiation, but it only affects trunking, not MAC address learning or violation actions.

1373
MCQmedium

A network administrator wants to secure remote CLI access to a Cisco router, moving beyond simple username/password authentication. Which approach best achieves this goal?

A.Use stronger or additional authentication controls to improve remote administrative access security
B.Replace SSH with Telnet to simplify troubleshooting
C.Configure an extended ACL to limit remote access to specific source IP addresses
D.Disable password authentication and rely solely on device location in the network
AnswerA

Implementing stronger or additional authentication controls—such as multi-factor authentication, AAA with TACACS+/RADIUS, or per-user credentials—directly addresses the security of the management plane. A static password alone is vulnerable to password guessing, credential theft, or replay. Strong authentication ensures that even if one factor is compromised, an attacker cannot complete the login process, protecting the device from unauthorized remote configuration.

Why this answer

The goal is to strengthen authentication beyond a simple password. Cisco AAA (Authentication, Authorization, and Accounting) using TACACS+ or RADIUS provides stronger, centralized authentication. Secure Shell (SSH) with key-based or two-factor authentication also enhances security.

Option A correctly describes this concept, while the other options either weaken security (B, D) or address access control via ACLs, which does not improve the authentication factor itself (C).

Exam trap

A common trap is thinking that limiting access with an ACL (option C) satisfies the goal, but ACLs restrict source addresses, not strengthen the authentication process. Another trap is confusing stronger authentication with simpler troubleshooting (B) or location-based trust (D).

Why the other options are wrong

B

Telnet transmits credentials in plaintext, making it less secure than SSH and opposite to the goal of stronger authentication.

C

An ACL restricts source addresses but does not strengthen the authentication factor itself; it is an authorization control, not an authentication improvement.

D

Removing password authentication and relying on location removes all credential verification, making the device vulnerable to unauthorized access from permitted locations.

When would these options actually be correct?

B

This option could be correct in a scenario where the question asks about troubleshooting network connectivity issues and emphasizes ease of access for administrators. If the focus were on simplifying access for troubleshooting rather than security, replacing SSH with Telnet might be considered appropriate.

C

In a hypothetical exam scenario where the question asks about a system that requires immediate access without any credentials for emergency situations, disabling authentication could be considered correct to prevent lockouts during critical failures.

D

In a question focused on network design where the goal is to optimize bandwidth and support multiple VLANs on a single connection, selecting trunk ports could be the correct answer. For instance, if the question asks how to efficiently manage VLAN traffic in a switched network environment, trunking would be appropriate.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of the trade-offs between security and ease of access, believing that simpler protocols like Telnet could facilitate quicker troubleshooting without recognizing the security implications.

C

Candidates might be tempted by the idea of avoiding lockouts, especially in high-pressure environments where quick access is crucial, leading them to overlook the severe security implications of disabling authentication.

D

Candidates may be tempted by this option because they associate trunk ports with advanced network configurations, mistakenly believing that they enhance overall security by managing multiple VLANs, rather than focusing on authentication methods.

1374
PBQhard

You are connected to R1. The network uses a single router with two subnets: 192.168.1.0/24 (connected to GigabitEthernet0/0) and 10.0.0.0/30 (connected to GigabitEthernet0/1). Configure an extended named ACL called 'FILTER_HTTP' that permits HTTP traffic (TCP port 80) from the 192.168.1.0/24 subnet to any destination, and includes an explicit deny statement to deny all other IP traffic. Apply the ACL inbound on GigabitEthernet0/0. Then verify that HTTP traffic is allowed and all other traffic is blocked.

Network Topology
G0/0192.168.1.1/24192.168.1.0/24G0/110.0.0.1/3010.0.0.0/30R1PC1ISP

Hints

  • Remember the implicit deny at the end of every ACL – you may not need an explicit deny, but the question asks to deny all other IP traffic.
  • Use the correct wildcard mask for the subnet 192.168.1.0/24: 0.0.0.255.
  • Apply the ACL to the interface that receives traffic from the internal subnet.
A.ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/0 ip access-group FILTER_HTTP in
B.access-list 100 permit tcp 192.168.1.0 0.0.0.255 any eq 80 access-list 100 deny ip any any interface GigabitEthernet0/0 ip access-group 100 in
C.ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 interface GigabitEthernet0/0 ip access-group FILTER_HTTP in
D.ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/1 ip access-group FILTER_HTTP in
AnswerA
solution
! R1
ip access-list extended FILTER_HTTP
permit tcp 192.168.1.0 0.0.0.255 any eq 80
deny ip any any
interface GigabitEthernet0/0
ip access-group FILTER_HTTP in

Why this answer

The task requires creating an extended named ACL 'FILTER_HTTP' that permits TCP port 80 from source 192.168.1.0/24 to any destination, and then denies all other IP traffic (the implicit deny will block everything else, but you must explicitly add a deny ip any any statement to make the intent clear). The ACL must be applied inbound on GigabitEthernet0/0. The solution uses the commands: ip access-list extended FILTER_HTTP, permit tcp 192.168.1.0 0.0.0.255 any eq 80, deny ip any any, and interface GigabitEthernet0/0, ip access-group FILTER_HTTP in.

Verification with show access-lists and show ip interface GigabitEthernet0/0 confirms the ACL and its application.

Exam trap

Pay attention to the requirement for a named ACL versus numbered ACL. Also, note that while the implicit deny exists, the question explicitly asks for a deny statement, so you must include it. Finally, ensure the ACL is applied to the correct interface and direction.

Why the other options are wrong

B

The specific factual error is that the ACL must be named 'FILTER_HTTP', but this option uses a numbered ACL (100).

C

The specific factual error is that the ACL does not include an explicit deny ip any any, which is needed to satisfy the requirement of denying all other IP traffic.

D

The specific factual error is that the ACL is applied to the wrong interface (GigabitEthernet0/1 instead of GigabitEthernet0/0).

Why candidates pick the wrong answer

B

Candidates might pick this because they know that extended ACLs can be numbered (100-199) and the permit/deny statements are correct, but they overlook the requirement for a named ACL.

C

Candidates might pick this because they know that ACLs have an implicit deny, so they think an explicit deny is unnecessary. However, the question explicitly requires a deny statement.

D

Candidates might pick this because they confuse the two interfaces or think that applying the ACL on the other interface might also work, but the direction and interface must match the requirement.

1375
MCQhard

A user reports that a laptop can connect to the correct SSID but repeatedly fails authentication when joining the WLAN. Which category of issue is most strongly indicated?

A.A security or authentication mismatch related to WLAN access
B.A missing OSPF router ID on the access point
C.A routed-port mismatch on the switch uplink
D.A DHCP relay problem on the client
AnswerA

The client can see and associate with the SSID, but the authentication exchange fails because of mismatched security parameters—such as an incorrect pre-shared key, incompatible WPA version, or an EAP/RADIUS misconfiguration on the WLAN profile. In 802.1X or WPA2/WPA3 PSK, the four-way handshake must complete before the client is granted access; when authentication credentials or cipher suites differ between client and AP, the handshake aborts, causing repeated association attempts and a visible SSID but no successful connection.

Why this answer

The strongest indication is a wireless security or authentication mismatch rather than a pure RF coverage problem. In practical terms, the laptop can already see and attempt to join the correct SSID, which means discovery is working. Repeated authentication failure points more directly to credentials, security settings, or authentication-policy alignment than to channel or signal absence.

This question is about recognizing the stage of failure. The client is finding the WLAN, but it is not being accepted onto it.

Exam trap

A common exam trap is selecting options related to routing protocols or DHCP relay issues when a client fails to authenticate on a WLAN. Candidates may incorrectly assume that IP configuration problems or routing mismatches cause authentication failures. However, authentication occurs before IP assignment, so DHCP or OSPF issues cannot cause repeated authentication failures.

This trap distracts from the correct focus on wireless security settings and credentials, which are the root cause when a client sees the SSID but cannot authenticate.

Why the other options are wrong

B

Incorrect. OSPF router IDs are relevant to routing protocols and do not affect wireless client authentication or SSID association processes.

C

Incorrect. Routed-port mismatches on switch uplinks affect wired network traffic forwarding but do not cause wireless authentication failures at the client level.

D

Incorrect. DHCP relay problems affect IP address assignment after authentication; since the client fails authentication repeatedly, DHCP issues are not the cause.

When would these options actually be correct?

B

If the question were about routing issues affecting network connectivity, such as a scenario where a device cannot communicate with other routers due to OSPF misconfigurations, then a missing OSPF router ID on the access point would be the correct answer.

C

If the exam question described a scenario where a device is unable to route traffic due to mismatched configurations between a switch and a router, specifically mentioning routed ports, then option C would be correct. For example, if a user reported that they could not access the internet despite being connected to the WLAN, and troubleshooting revealed a routed-port mismatch, this option would apply.

D

In a scenario where a user reports that their device connects to the SSID but cannot obtain an IP address, and the question specifically asks about issues related to IP assignment rather than authentication, option D would be correct as it directly relates to DHCP relay configurations.

Why candidates pick the wrong answer

B

Candidates might choose this option due to a misunderstanding of the relationship between routing and wireless connectivity, mistakenly believing that routing issues could impact WLAN access and authentication.

C

Candidates may choose this option due to a misunderstanding of network layers, mistakenly linking switch configurations to wireless issues. They might also recall scenarios where switch configurations impacted overall connectivity, leading to confusion about the specific context of WLAN authentication.

D

Candidates may choose this option due to a misunderstanding of the authentication process, thinking that if a device connects to the SSID, it must be receiving an IP address, and therefore any issues must be related to DHCP rather than authentication.

1376
MCQhard

Based on the exhibit, why is the ACL blocking more traffic than intended?

A.Because the ACL denies all TCP traffic to the server instead of only Telnet.
B.Because Telnet uses UDP, not TCP.
C.Because the ACL should be a standard ACL, not an extended ACL.
D.Because the host keyword can never be used with TCP statements.
AnswerA

The ACL statement is missing the destination port qualifier (eq 23) after the destination host, so it matches any TCP segment destined to that server, not just Telnet. As a result, SSH, HTTPS, and any other TCP service are also denied, which is why more traffic is being blocked than the administrator intended. To restrict only Telnet, the extended ACL must include 'eq 23' or 'eq telnet' at the end.

Why this answer

The ACL is blocking more traffic than intended because it uses a broad deny against all TCP traffic to the server instead of only the one service that should be denied. In practical terms, the requirement is narrow, but the configured entry is much wider. As a result, multiple TCP-based applications to that server are blocked, not just the intended one.

This is a classic precision problem in ACL design. It tests whether you can compare what the business requirement says against what the ACL actually matches.

Exam trap

The exam trap here is assuming that denying TCP traffic to a server without specifying the Telnet port will only block Telnet sessions. In reality, the ACL entry without the destination port qualifier matches all TCP traffic to that server, blocking multiple services unintentionally. This mistake often arises from confusing standard ACLs, which filter only by source IP, with extended ACLs that require explicit port numbers for service-specific filtering.

Candidates may overlook the need for the 'eq 23' qualifier for Telnet, leading to broader traffic denial and failing the question.

Why the other options are wrong

B

This option is incorrect because Telnet uses TCP as its transport protocol, not UDP. Therefore, denying TCP traffic is relevant for blocking Telnet, and the statement about UDP is factually wrong.

C

This option is incorrect because standard ACLs filter only by source IP address and cannot filter by protocol or port. The question requires filtering by service (Telnet), which necessitates an extended ACL, making this option invalid.

D

This option is incorrect because the 'host' keyword is valid in extended ACLs and is commonly used to specify a single IP address for precise matching. There is no restriction against using 'host' with TCP statements.

When would these options actually be correct?

B

In a different question scenario where the focus is on a misconfigured ACL affecting UDP traffic, the option could be correct if the question stated that Telnet-like services were incorrectly configured to use UDP instead of TCP, thus blocking legitimate traffic.

C

In a different scenario, if the question asked why a network administrator mistakenly configured a standard ACL to block specific IP addresses without considering port numbers, this option could be correct. The question would need to focus on the limitations of standard ACLs in filtering traffic based on protocols.

D

In a different exam scenario where the question specifies that the ACL is incorrectly configured to block all TCP traffic and explicitly states that the host keyword cannot be used with TCP statements, this option would be correct. For example, if the question asked why a specific ACL configuration is invalid due to the misuse of keywords, then this option would apply.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of protocol types, confusing TCP and UDP, especially if they have encountered similar questions about ACLs and protocol filtering in their studies.

C

Candidates might choose this option due to a misunderstanding of ACL types, believing that standard ACLs are sufficient for all filtering needs, especially if they are familiar with basic ACL concepts but not the specifics of extended ACL functionality.

D

Candidates might choose this option due to a misunderstanding of ACL syntax and the role of the host keyword, leading them to believe that it is universally incompatible with TCP configurations.

1377
PBQmedium

You are connected to SW1 via the console. SW1 is a Layer 2 switch with two VLANs (10 - Sales, 20 - Engineering). Port G0/1 is connected to a PC in VLAN 10, and port G0/2 is connected to a PC in VLAN 20. The switch needs to be configured to allow inter-VLAN communication using an external router connected to port G0/3. Currently, the PCs cannot communicate across VLANs. Configure the switch to support Router-on-a-Stick with VLAN 10 as the native VLAN on the trunk.

Network Topology
G0/1G0/1G0/3G0/3G0/0G0/0PC1SW1R1PC2

Hints

  • Remember to set the trunk port encapsulation if needed (though modern switches default to dot1q).
  • The native VLAN on the trunk must match what the router expects.
  • Use switchport mode access for ports connecting to end devices.
A.Configure G0/1 as access VLAN 10, G0/2 as access VLAN 20, G0/3 as trunk with native VLAN 10, and allow VLANs 10 and 20 on the trunk.
B.Configure G0/1 as access VLAN 10, G0/2 as access VLAN 20, G0/3 as trunk with native VLAN 1, and allow VLANs 10 and 20 on the trunk.
C.Configure G0/1 as access VLAN 10, G0/2 as access VLAN 20, G0/3 as trunk with native VLAN 10, but do not allow VLAN 10 on the trunk.
D.Configure G0/1 as trunk with native VLAN 10, G0/2 as trunk with native VLAN 20, G0/3 as trunk with native VLAN 10, and allow VLANs 10 and 20 on all trunks.
AnswerA
solution
! SW1
vlan 10
name Sales
vlan 20
name Engineering
interface GigabitEthernet0/1
switchport mode access
switchport access vlan 10
interface GigabitEthernet0/2
switchport mode access
switchport access vlan 20
interface GigabitEthernet0/3
switchport mode trunk
switchport trunk native vlan 10

Why this answer

Access ports assign PCs to their respective VLANs. The trunk port carries multiple VLANs to the router, and setting the native VLAN to 10 ensures untagged frames on the trunk belong to VLAN 10, which the router's subinterface for VLAN 10 will handle as untagged.

Exam trap

A common trap is to leave the native VLAN as the default VLAN 1 or to forget that the native VLAN must be explicitly allowed on the trunk. Also, candidates may incorrectly configure PC-facing ports as trunks instead of access ports. Always verify the native VLAN matches the router's untagged subinterface and that the allowed VLAN list includes all necessary VLANs.

Why the other options are wrong

B

The native VLAN must match the VLAN that the router's subinterface handles as untagged. Setting it to VLAN 1 violates the requirement.

C

The trunk must carry all VLANs that need inter-VLAN communication. Excluding VLAN 10 prevents its traffic from reaching the router.

D

PCs are end devices that expect untagged frames; they should be connected to access ports, not trunk ports.

Why candidates pick the wrong answer

B

Candidates often default to native VLAN 1 because it is the default native VLAN on Cisco switches, forgetting that the requirement specifies VLAN 10.

C

Some candidates think that because VLAN 10 is the native VLAN, it is automatically allowed, but the 'allowed vlan' list must explicitly include it.

D

Candidates might mistakenly think that all ports need to be trunks to carry multiple VLANs, not understanding that access ports assign a single VLAN to the connected device.

1378
MCQmedium

Exhibit: An engineer wants a device to send only warning messages and more critical events to a syslog server. Which logging level should be configured?

A.logging trap debugging
B.logging trap warnings
C.logging trap notifications
D.logging trap informational
AnswerB

The syslog severity scale numbers levels from 0 (emergencies) to 7 (debugging), with warnings at level 4. Issuing 'logging trap warnings' instructs the device to send only messages at severity 4 and above (i.e., 0-4), which precisely matches the engineer's requirement to send only warning-level and more severe messages while excluding notifications and lower. This is the exact command for filtering to warnings and critical alerts.

Why this answer

Syslog severity levels include lower numbers for more severe events. Warning is level 4, so setting logging trap warnings sends level 4, 3, 2, 1, and 0 messages.

Exam trap

A frequent exam trap is selecting 'logging trap debugging' or 'informational' because these options seem to provide comprehensive logging. However, these levels include all messages, even low-priority informational and debug messages, which can overwhelm the syslog server and make it difficult to identify critical issues. Another trap is misunderstanding the syslog severity numbering, assuming higher numbers mean higher severity, when in fact, lower numbers indicate more critical events.

This confusion leads to incorrect trap level configuration and ineffective monitoring.

Why the other options are wrong

A

The option 'logging trap debugging' sets the trap level to 7, which includes all syslog messages from debugging (least severe) up to emergencies (most severe). This floods the syslog server with excessive data, beyond just warnings and critical events, making it unsuitable for the requirement.

C

The option 'logging trap notifications' sets the trap level to 5, which includes notifications and all more severe messages. However, notifications are less severe than warnings, so this setting would include informational messages that are not requested, making it incorrect.

D

The option 'logging trap informational' sets the trap level to 6, which includes informational messages and all more severe messages. This level is less severe than warnings and includes many more messages than requested, so it does not meet the requirement.

When would these options actually be correct?

A

In a different scenario where an engineer needs to troubleshoot a network issue and requires detailed information about system operations, 'logging trap debugging' would be appropriate to capture all levels of logs for comprehensive analysis.

C

In a different scenario where the requirement is to send all notifications, including warnings, to a syslog server without filtering, 'logging trap notifications' would be the correct answer. For example, if the question asked for all significant events, including warnings and alerts, this option would be appropriate.

D

If the question specified that the engineer wanted to monitor all events, including informational messages, to gain a comprehensive view of the system's status, then 'logging trap informational' would be the correct choice. This could be relevant in a scenario where detailed logging is necessary for troubleshooting.

Why candidates pick the wrong answer

A

Candidates may choose this option due to a misunderstanding of logging levels, thinking that debugging information could provide valuable insights, even when only warnings and critical events are required.

C

Candidates may be tempted to choose this option because 'notifications' sounds like it would include important messages, leading them to believe it aligns with the need to capture critical events, despite it being broader than required.

D

Candidates may choose this option because they associate 'informational' with important system messages and believe that capturing all events would provide a fuller picture, not realizing it contradicts the specific requirement of filtering out less critical logs.

1379
MCQhard

A host with address 172.16.5.10/23 wants to determine whether 172.16.6.20 is on the same local network. What is the correct conclusion?

A.It is on the same local network because both addresses begin with 172.16.
B.It is on the same local network because /23 covers all addresses in 172.16.5.x and 172.16.6.x
C.It is on a different network, so the host should use the default gateway
D.It is on a different network, so ARP will resolve it across the router automatically
AnswerC

The host determines the network address by performing a bitwise AND operation between its IP address (172.16.5.10) and its /23 subnet mask (255.255.254.0), resulting in 172.16.4.0. It then applies the same subnet mask to the target IP (172.16.6.20), yielding 172.16.6.0. Since these calculated network addresses differ, the host concludes the target is on a different network. Consequently, it must forward traffic to its default gateway for routing.

Why this answer

A /23 prefix covers two consecutive /24 ranges. In plain language, that means the network boundaries move in blocks of 2 in the third octet. The address 172.16.5.10/23 belongs to the 172.16.4.0/23 network, which covers 172.16.4.x and 172.16.5.x. The destination 172.16.6.20 belongs to a different /23 block, so it is not on the same local network.

This question checks whether you can think beyond default /24 boundaries and understand how a broader prefix changes the local network range. The host would therefore need to use its default gateway to reach 172.16.6.20, because that destination is off-subnet relative to the /23 in use.

Exam trap

Don't assume addresses with the same initial octets are in the same subnet; always calculate based on the subnet mask.

Why the other options are wrong

A

This option is incorrect because the addresses 172.16.5.10 and 172.16.6.20 belong to different subnets; 172.16.6.20 is in the 172.16.6.0/23 subnet, while 172.16.5.10 is in the 172.16.5.0/23 subnet.

B

This option is incorrect because a /23 subnet mask allows for addresses in the range of 172.16.4.0 to 172.16.5.255, meaning 172.16.6.20 is outside this range and not on the same local network.

D

Option D is incorrect because ARP (Address Resolution Protocol) operates within the same local network and cannot resolve addresses across routers. Since 172.16.6.20 is on a different network than 172.16.5.10, ARP cannot automatically resolve it.

When would these options actually be correct?

A

If the question stated that both addresses were part of a larger subnet, such as 172.16.0.0/16, then this option would be correct, as both addresses would indeed be on the same local network.

B

If the question stated that the subnet mask was /22 instead of /23, then option B would be correct, as a /22 subnet would encompass both 172.16.5.x and 172.16.6.x addresses, allowing them to be on the same local network.

D

If the question stated that both addresses were on the same local network but required ARP to resolve a device's MAC address for communication, then option D would be correct. For example, if both addresses were within the same subnet and the question asked about resolving a MAC address, D would apply.

Why candidates pick the wrong answer

A

Candidates may be drawn to this option because it highlights a common misconception that addresses starting with the same octets are always in the same network, ignoring the significance of the subnet mask.

B

Candidates may be tempted by this option because they recognize that both addresses share the same initial octets, leading them to mistakenly assume they are in the same subnet without considering the subnet mask.

D

Candidates might choose this option due to a misunderstanding of ARP's functionality, believing it can resolve addresses across different networks, which is a common misconception among those with limited networking knowledge.

1380
PBQhard

You are connected to R1. Use RESTCONF to retrieve all operational interface statistics from the ietf-interfaces YANG module, then modify the description of GigabitEthernet0/1 to 'Link to R2 via RESTCONF' using a PATCH request. The device is reachable at 203.0.113.1 with port 443, username 'admin', password 'cisco123'. Identify the error that would occur if you used a PATCH with Content-Type: application/json instead of application/yang-data+json.

Network Topology
G0/0203.0.113.1/24InternetR1RESTCONF client

Hints

  • RESTCONF base URI is always /restconf.
  • Use the YANG module 'ietf-interfaces' for operational state and configuration.
  • The correct media type for RESTCONF is application/yang-data+json, not generic application/json.
A.The server returns a 415 Unsupported Media Type error because RESTCONF requires the Content-Type header to be application/yang-data+json.
B.The server returns a 400 Bad Request error because the JSON payload is malformed when using application/json.
C.The server returns a 404 Not Found error because the URI is incorrect when using application/json.
D.The server returns a 204 No Content response but ignores the description change because application/json is not supported.
AnswerA
solution
! R1
GET https://203.0.113.1/restconf/data/ietf-interfaces:interfaces-state/interface
Accept: application/yang-data+json
PATCH https://203.0.113.1/restconf/data/ietf-interfaces:interfaces/interface=GigabitEthernet0/1
Content-Type: application/yang-data+json
{"ietf-interfaces:interface": [{"name": "GigabitEthernet0/1", "description": "Link to R2 via RESTCONF"}]}

Why this answer

The correct base URI for RESTCONF is https://203.0.113.1/restconf. To retrieve operational interface statistics, use GET with the path /data/ietf-interfaces:interfaces-state/interface. For the PATCH to modify the description, the URI must target /data/ietf-interfaces:interfaces/interface=GigabitEthernet0/1 with a JSON payload containing the 'description' leaf.

The required Content-Type and Accept headers must be 'application/yang-data+json'. Using 'application/json' will result in a 415 Unsupported Media Type error because RESTCONF requires the specific YANG media type.

Exam trap

The exam tests your knowledge of RESTCONF's strict media type requirements. Many candidates assume that application/json is acceptable because it is common in REST APIs, but RESTCONF specifically requires 'application/yang-data+json'. Remember that using any other media type results in a 415 error.

Why the other options are wrong

B

The specific factual error is that a 400 Bad Request is not triggered by an incorrect Content-Type; it is triggered by malformed syntax or invalid data.

C

The specific factual error is that the Content-Type header does not affect resource discovery; it only affects how the server interprets the payload.

D

The specific factual error is that an unsupported media type results in a client error (4xx), not a success response (2xx).

Why candidates pick the wrong answer

B

Candidates might think that using a different media type would cause a parsing error, leading to a 400 response.

C

Candidates might confuse the error code for a missing resource with a media type error, especially if they have seen 404 errors in other contexts.

D

Candidates might think the server silently ignores the unsupported media type and returns a success code, which is a common misconception about REST APIs.

1381
MCQhard

Refer to the exhibit. A network engineer is troubleshooting an EtherChannel on R1 that is not passing traffic. The output of the show etherchannel summary command is displayed. What is the most likely cause?

A.The local switch is configured with LACP passive while the remote switch is set to LACP active.
B.One side is configured with LACP active and the other side is configured with mode 'on' (static).
C.The remote switch is configured with PAgP desirable while the local switch uses LACP.
D.The port-channel member interfaces are configured as access ports, preventing LACP from negotiating.
AnswerB

With LACP active on one side and mode 'on' on the fabric peer, the 'on' port forces an EtherChannel statically and never transmits LACP PDUs, so the active LACP port never receives a response and cannot move the member port to a bundled state. The port-channel interface may still be administratively up and declared up (SU) because it exists in configuration, but the physical member ports remain in a down (D) state because no LACP negotiation completed. This exact combination produces the (D) flags on member ports while the port-channel itself remains up, making it the correct cause.

Why this answer

The 'show etherchannel summary' output shows the port-channel is down (flags indicate 'D' for down), and the most common cause when one side is configured with LACP active and the other with mode 'on' (static) is a protocol mismatch. LACP active expects to negotiate with another LACP-enabled port, but static mode 'on' forces the link up without negotiation, causing the EtherChannel to fail to form. This mismatch prevents the exchange of LACP frames, leaving the bundle in an error-disabled or non-functional state.

Exam trap

Cisco often tests the misconception that LACP passive/active is incompatible, but the real trap is confusing static mode 'on' (which disables negotiation) with LACP modes, leading candidates to overlook the protocol mismatch between LACP and static configuration.

Why the other options are wrong

A

LACP passive is not incompatible with LACP active.

C

PAgP/LACP mismatch leads to suspended state, not down; the exhibit's (D) indicates the link is not up, which points to LACP negotiation failure rather than protocol mismatch.

D

LACP negotiation is independent of the access/trunk configuration.

1382
PBQmedium

You are connected to the console of R1. The network has a point-to-point serial link between R1 and R2. The link is down and the line protocol is down. The cable is a DCE/DTE crossover, and R1 is the DCE. The initial configuration shows the interface with an IP address but no clock rate set.

Network Topology
S0/0/0 .1/30S0/0/0 .2/30serial DCER1R2

Hints

  • The DCE side must provide the clock rate.
  • Check the cable type using 'show controllers'.
  • Common clock rates are 64000, 128000, 256000, etc.
A.Configure the clock rate on R1's serial interface.
B.Configure the clock rate on R2's serial interface.
C.Replace the serial cable with a straight-through cable.
D.Set the encapsulation on both ends to PPP.
AnswerA
solution
! R1
interface Serial0/0/0
clock rate 128000

Why this answer

On a serial DCE cable, the DCE end must configure a clock rate to provide timing. Without it, the line protocol stays down. Setting 'clock rate 128000' on R1 resolved the issue.

Exam trap

Remember that 'down/down' indicates a Layer 1 issue. On serial links, the DCE must provide clocking. Do not confuse DCE/DTE roles or jump to Layer 2 solutions like encapsulation.

Why the other options are wrong

B

The DTE end does not set clock rate; only the DCE end does.

C

Serial cables are always DCE/DTE crossover; straight-through cables are for Ethernet.

D

Encapsulation mismatch causes protocol down, not line protocol down; the line protocol is down due to no clock.

Why candidates pick the wrong answer

B

Candidates may think both ends need clock rate or confuse DCE/DTE roles.

C

Candidates might think a cable mismatch causes the down/down state, but the cable is correct.

D

Candidates may recall that encapsulation mismatch can cause issues, but here the problem is at Layer 1.

1383
MCQmedium

Which pairing is correct?

A.JSON — data modeling language used to define network schemas such as YANG modules
B.YANG — lightweight interchange format built from curly braces and arrays
C.RESTCONF — protocol that can use YANG-defined data models over HTTP-based access
D.NETCONF — spanning-tree enhancement for rapid convergence
AnswerC

RESTCONF is an IETF-standard protocol (RFC 8040) that exposes YANG-defined data models through a RESTful API over HTTP/HTTPS. It uses HTTP methods like GET, POST, PUT, PATCH, and DELETE to access configuration and state data, making it ideal for programmatic network automation and integration with web-based tooling. The pairing is correct because RESTCONF specifically bridges YANG models with HTTP-based access.

Why this answer

RESTCONF is an HTTP-based API approach that commonly uses YANG-defined data models. JSON is a data-interchange format, YANG is the data modeling language, and NETCONF is a network management protocol rather than an STP feature.

Exam trap

A frequent exam trap is confusing JSON with YANG or NETCONF with spanning-tree enhancements. JSON is a data format, not a modeling language, so pairing it with YANG modules is incorrect. Similarly, NETCONF is often mistakenly thought to be related to spanning-tree protocols, but it is actually a network configuration protocol.

Candidates might also confuse YANG’s role with JSON’s syntax or RESTCONF’s protocol function. This confusion arises because these technologies often work together but serve distinct purposes. Understanding each technology’s specific role prevents selecting incorrect answers based on superficial similarities.

Why the other options are wrong

A

Option A incorrectly pairs JSON with YANG modules as a data modeling language. JSON is a data interchange format used to represent data but does not define schemas or models. YANG is the actual modeling language used to define network data structures, so this pairing is false.

B

Option B wrongly describes YANG as a lightweight interchange format built from curly braces and arrays, which actually describes JSON syntax. YANG is a modeling language that defines network data hierarchies and constraints, not a data format with JSON-like syntax.

D

Option D falsely claims NETCONF is a spanning-tree enhancement for rapid convergence. NETCONF is a network configuration protocol using XML over SSH and has no relation to spanning-tree protocols or their convergence mechanisms, making this option incorrect.

When would these options actually be correct?

A

If the exam question asked about data modeling languages specifically for network configurations, and the context was about defining schemas in a broader sense, then option A could be correct if it referred to a hypothetical scenario where JSON was being used in a similar capacity as YANG.

B

If the question asked for a description of a data format used for configuration management that is similar to JSON, or if it specifically referenced YANG's role in defining data structures in a JSON-like syntax, then option B could be considered correct.

D

If the exam question asked about protocols related to network topology or enhancements to spanning-tree protocols, and if it specified a focus on rapid convergence techniques, then a candidate might correctly identify NETCONF as a relevant technology in that context.

Why candidates pick the wrong answer

A

Candidates might find this option tempting due to a misunderstanding of JSON's role in data interchange and its potential use in network configurations, leading them to incorrectly associate it with data modeling.

B

Candidates may confuse YANG with JSON due to their roles in data representation and may mistakenly associate YANG's syntax with JSON's structure, leading them to choose this option despite its inaccuracies.

D

Candidates may be tempted by this option due to the familiarity of NETCONF with network management and configuration, leading to confusion with concepts related to network efficiency and convergence.

1384
MCQmedium

Why is HTTPS usually preferred over HTTP when accessing a controller API?

A.Because HTTPS provides encrypted transport for API traffic.
B.Because HTTPS automatically replaces authentication.
C.Because HTTPS is the only format that can carry JSON.
D.Because HTTP cannot carry controller data at all.
AnswerA

HTTPS is preferred because it wraps API traffic in Transport Layer Security (TLS), encrypting the payload and headers so that sensitive data such as authentication tokens, controller commands, and responses cannot be read or modified by an eavesdropper. The encryption also provides integrity checking, preventing man-in-the-middle tampering. This transport-level confidentiality and integrity is the primary security advantage HTTPS has over plaintext HTTP.

Why this answer

HTTPS is preferred because it protects the communication with encryption while it crosses the network. In practical terms, controller APIs often carry tokens, credentials, device state, or configuration information that should not be exposed in clear text. HTTPS helps protect those requests and responses in transit.

This does not make HTTPS the same thing as JSON, nor does it remove the need for authentication. It is simply the more secure transport choice for sensitive API communication.

Exam trap

Avoid assuming that HTTPS improves speed or handles authentication. Focus on its role in securing data in transit.

Why the other options are wrong

B

This option is incorrect because HTTPS does not replace authentication; it enhances security by encrypting the transport layer, but authentication mechanisms still need to be implemented separately.

C

This option is incorrect because both HTTPS and HTTP can carry JSON data; JSON is a data format independent of the transport protocol used. Thus, HTTPS is not the only format capable of transmitting JSON.

D

This option is wrong because HTTP can indeed carry controller data; it is a fundamental protocol for transmitting data over the web. Both HTTP and HTTPS can be used to send and receive data, including JSON payloads, between clients and APIs.

When would these options actually be correct?

B

In a different question that asks about the benefits of HTTPS in a context where authentication methods are being discussed, one might argue that HTTPS simplifies the authentication process by securing credentials during transmission, making it seem like it replaces the need for separate authentication mechanisms.

C

If the exam question were to ask specifically about data formats and their compatibility with transport protocols, stating that HTTPS is the only format that can carry JSON would be correct if the context were limited to a scenario where only HTTPS is allowed for security reasons, and the question explicitly states that JSON is the only data format in use.

D

This option would be correct in a scenario where the question specifically states that HTTP is incapable of carrying any data types, such as in a theoretical context where HTTP is defined as a legacy protocol that has been deprecated for all data transmission. For example, a question might ask about the limitations of HTTP in a specific outdated system.

Why candidates pick the wrong answer

B

Candidates may choose this option due to a misunderstanding of HTTPS's role in security, conflating encryption with authentication, leading them to believe that HTTPS inherently provides authentication features.

C

Candidates may choose this option due to a misunderstanding of the relationship between transport protocols and data formats, mistakenly believing that HTTPS inherently supports certain data formats while HTTP does not.

D

Candidates might choose this option due to a misunderstanding of HTTP's capabilities, thinking that the lack of security in HTTP implies a total inability to transmit any data, leading to confusion about its functionality.

1385
Multi-Selectmedium

Which two statements accurately describe the value of source restriction on administrative access?

Select 2 answers
A.It reduces the set of network locations from which administrative access is allowed.
B.It can make access monitoring and filtering easier to manage.
C.It removes the need for SSH or other secure transports.
D.It makes logging unnecessary.
E.It can be used only for wireless management.
AnswersA, B

Restricting administrative access by source address narrows the potential attack surface to only trusted IPs or subnets. This is a fundamental security control because it minimizes the number of network locations from which a malicious actor could even attempt to authenticate or exploit management protocols. Without such restrictions, the management plane is exposed to the entire reachable network, dramatically increasing the risk of unauthorized access.

Why this answer

Source restriction improves security by reducing the number of places from which administrative traffic is expected and permitted. In practical terms, this makes exposure smaller and monitoring clearer. It does not replace secure protocols or identity controls, but it strengthens the overall design.

This is a layered-management-security question because it emphasizes how source restriction complements other controls.

Exam trap

A common exam trap is to believe that source restriction removes the need for secure transport protocols like SSH or makes logging unnecessary. Some candidates mistakenly think that limiting source IP addresses alone fully secures administrative access. However, source restriction only controls where connections can originate; it does not encrypt data or authenticate users.

Ignoring secure protocols or logging can leave management sessions vulnerable to interception or unauthorized use. The exam tests understanding that source restriction is a complementary control, not a replacement for transport security or auditing.

Why the other options are wrong

C

Incorrect because source restriction does not replace the need for secure transport protocols like SSH; encryption and authentication remain essential for secure management.

D

Incorrect because logging is still necessary to maintain visibility and audit trails of administrative access attempts, even when source restriction is applied.

E

Incorrect because source restriction is not limited to wireless management; it applies broadly to all administrative access methods on Cisco devices.

When would these options actually be correct?

C

If the exam question asked about the benefits of implementing a network policy that allows access only from trusted devices, then this option could be correct, as it might imply that secure transports are not necessary when all access is from a secure, trusted source.

D

In a hypothetical exam scenario where the question states that a specific system has implemented comprehensive real-time monitoring and alerting mechanisms that negate the need for logging, option D could be considered correct. This would imply that all actions are monitored live, making logging redundant.

E

If the exam question specifically asked about the management of wireless networks and stated that source restriction is a feature exclusive to wireless management systems, then option E could be correct. For example, a question might ask about security measures unique to wireless administrative access.

Why candidates pick the wrong answer

C

Candidates may find this option tempting due to a misunderstanding of network security principles, believing that restricting access inherently negates the need for secure communication methods like SSH.

D

Candidates may choose this option due to a misunderstanding of the role of logging in security practices, believing that source restrictions alone can suffice for security oversight without realizing the importance of maintaining logs for accountability.

E

Candidates may find this option tempting due to the common association of security measures with wireless networks, leading them to mistakenly believe that source restriction is exclusively applicable to wireless management.

1386
Matchingmedium

Match each IPv4-related concept to its most accurate role.

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

Concepts
Matches

Defines which destinations are local versus remote

Next hop used for off-subnet traffic

Address used to reach all hosts in the local subnet

Address identifying one device in the subnet

Why these pairings

The IPv4 address uniquely identifies a host on an IP network. The subnet mask distinguishes the network and host portions of the address, determining the local subnet. The default gateway is the router interface that forwards traffic to destinations outside the local subnet.

The DNS server resolves domain names to IP addresses, enabling name-based communication. Each concept plays a distinct and essential role in IPv4 networking.

Exam trap

Do not confuse the function of the IP address with other network layer concepts like subnet mask or default gateway. The IP address is the unique identifier for a host.

1387
MCQeasy

Which IPv6 address type is automatically created on an interface and used for link-local communication?

A.Unique local
B.Global unicast
C.Link-local
D.Anycast
AnswerC

Link-local IPv6 addresses are automatically created on every IPv6-enabled interface without any manual configuration or stateful protocol. They use the FE80::/10 prefix and are derived from the interface's MAC address (or a privacy-generated value) using EUI-64 or RFC 7217. Their scope is strictly the local link, enabling Neighbor Discovery Protocol, address resolution, and router discovery even before any other global address is present. Because they are always present, they are the correct answer to which IPv6 address type is auto-created.

Why this answer

IPv6 interfaces automatically generate a link-local address in FE80::/10 for local-segment functions such as neighbor discovery.

Exam trap

Be careful not to confuse link-local addresses with global or unique local addresses, which are not automatically generated and serve different purposes.

Why the other options are wrong

A

Unique local addresses (ULAs) are designed for local communications within a site and are not automatically created on an interface for local-link communication. They require manual configuration and are not used for link-local purposes.

B

Global unicast addresses are routable addresses used for communication over the internet and are not automatically created for local-link communication. They require configuration and are not limited to a single local network segment.

D

Anycast addresses are not automatically created on an interface for local-link communication; they are assigned to multiple interfaces to allow for routing to the nearest one. Therefore, they do not serve the same purpose as link-local addresses.

When would these options actually be correct?

A

If the exam question asked for an IPv6 address type that is used for private communication within a specific organization or site, without the need for global routing, then 'Unique local' would be the correct answer.

B

If the question asked which IPv6 address type is used for communication over the internet and is routable globally, then 'Global unicast' would be the correct answer. This scenario would focus on addressing types suitable for broader network communication rather than local-link.

D

If the question were to ask about the address type that allows for communication with the nearest instance of a service, such as a DNS server, in a multi-homed environment, then 'Anycast' would be the correct answer. This scenario would focus on routing and service discovery rather than local-link communication.

Why candidates pick the wrong answer

A

Candidates may confuse unique local addresses with link-local addresses due to their similar purpose of facilitating local communication, leading them to mistakenly select this option when considering local networking scenarios.

B

Candidates may confuse global unicast addresses with link-local addresses due to their understanding of IPv6 addressing and the need for unique addresses in a network, leading them to mistakenly think global unicast is relevant for local communication.

D

Candidates may confuse anycast with link-local addresses due to their shared use in network communication. The term 'local' in anycast might mislead them to think it relates to local-link usage.

1388
MCQhard

A network administrator notices that syslog messages from a core router are arriving at the syslog server with timestamps that are hours behind other devices. The router’s NetFlow exports also show incorrect start and end times for flows, making traffic analysis unreliable. The administrator verifies that all router interfaces are up and that the SNMP community strings on the router match the NMS.

A.The logging trap level is set to informational, so only high-severity messages are sent with correct timestamps.
B.The router’s NTP client is configured with an incorrect authentication key.
C.The SNMP v3 user’s privacy password is incorrect, causing the NMS to reject syslog traps.
D.The IP flow cache timeout is set too low, causing NetFlow timestamps to appear skewed.
AnswerB

NTP can use authentication keys to verify server identity. If the client key does not match the server’s key, the router will not trust the time updates and will fail to synchronize. This leaves the router’s clock uncorrected, causing incorrect timestamps in syslog and NetFlow records.

Why this answer

The router's timestamps are incorrect for both syslog messages and NetFlow exports, which points to a system-wide time synchronization issue. NTP (Network Time Protocol) is responsible for maintaining accurate time on network devices, and if the NTP client is configured with an incorrect authentication key, it will fail to synchronize with the NTP server, causing the router's clock to drift. This explains why all time-stamped data (syslog and NetFlow) is consistently behind.

Exam trap

Cisco often tests the distinction between time synchronization issues (NTP) and logging/SNMP configuration issues, so candidates may incorrectly attribute timestamp problems to syslog or SNMP settings rather than the underlying system clock.

Why the other options are wrong

A

Logging trap level controls which severity messages are forwarded, not the accuracy of the timestamps.

C

SNMP v3 misconfiguration impacts SNMP traps, not syslog messages, which are sent independently via a different transport.

D

Cache timeout affects flow export frequency, not the accuracy of the timestamps inside the flow data.

1389
MCQmedium

Why does DNS make networks easier for people to use?

A.It lets people use memorable names instead of raw IP addresses.
B.It assigns IP addresses automatically.
C.It replaces the need for default gateways.
D.It elects the root bridge for STP.
AnswerA

DNS translates easy-to-remember domain names, such as www.example.com, into the numeric IP addresses that networking equipment uses for packet delivery. This abstraction lets people access resources without memorizing long dotted-decimal or IPv6 hexadecimal strings. Without this name-to-address mapping, users would need to track raw IP addresses for every service, which is impractical and error-prone.

Why this answer

DNS makes networks easier to use because it lets people work with names instead of memorizing numeric IP addresses. In practical terms, users can remember a server name much more easily than a string of numbers. DNS creates that naming layer while the network still uses IP underneath.

This usability benefit is one of the main reasons DNS is so important in everyday network operations.

Exam trap

A frequent exam trap is mistaking DNS for DHCP or routing functions. Some candidates incorrectly believe DNS assigns IP addresses automatically, which is actually the role of DHCP. Others think DNS replaces default gateways or participates in spanning-tree protocol (STP) operations, which it does not.

This confusion arises because DNS, DHCP, routing, and STP are all fundamental network services but serve distinct purposes. Misunderstanding these roles can lead to selecting incorrect answers that sound plausible but do not match DNS’s actual function of name resolution.

Why the other options are wrong

B

Option B is incorrect because DHCP, not DNS, is responsible for automatically assigning IP addresses to devices on a network. DNS only resolves names to IP addresses after assignment.

C

Option C is incorrect because DNS does not replace default gateways. Default gateways are necessary for routing traffic outside the local subnet, a function unrelated to DNS name resolution.

D

Option D is incorrect because DNS has no role in Spanning Tree Protocol (STP) operations, including root bridge election, which is a Layer 2 loop prevention mechanism.

When would these options actually be correct?

B

In a question focused on DHCP functionalities, such as 'What protocol is responsible for automatically assigning IP addresses to devices on a network?', option B would be correct as it directly addresses DHCP's role in IP address assignment.

C

In a question focused on network architecture or routing protocols, where the function of default gateways is being discussed, this option could be correct if it stated that DNS can help in simplifying network configurations by providing hostname resolution for devices behind a default gateway.

D

If the exam question were about the functions of network protocols in a LAN environment, specifically asking which protocol is responsible for electing the root bridge in STP, then option D would be correct as it directly relates to the role of STP in network topology management.

Why candidates pick the wrong answer

B

Candidates may confuse DNS with DHCP due to their complementary roles in network management, leading them to mistakenly associate DNS with automatic IP address assignment.

C

Candidates might choose this option due to a misunderstanding of network components, conflating DNS's role in name resolution with the routing functions performed by default gateways, leading to confusion about their distinct purposes.

D

Candidates may find this option tempting because they might confuse DNS with other network protocols that manage network topology, leading them to incorrectly associate DNS with STP functions.

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