CCNA Mock Exam 80 — 25 Questions

Question 1

A router has a static route and a RIP route for the same destination prefix. What is the primary reason the static route is preferred over the RIP route?

Accepted Answer

Because the static route has a lower administrative distance for the same prefix.. The static route is preferred because both routes describe the same destination prefix and the static route has the lower administrative distance. In practical terms, longest-prefix match does not break the tie because the prefixes are equal. The router then compares source trust, and static routing wins over RIP by default.

This is a core route-selection concept and a very exam-relevant comparison.

Answer

Because RIP can never be installed when static routing is configured anywhere.

Answer

Because RIP is valid only for host routes.

Answer

Because static routes are always more specific than RIP routes.

Question 2

A network engineer is troubleshooting a link between two Cisco switches that are connected via a 1000BASE-LX SFP transceiver. Hosts on VLAN 10 on Switch A cannot ping the default gateway on Switch B. The interface on Switch A is up, but the engineer notices CRC errors incrementing. What should the engineer do to resolve this issue?

Accepted Answer

Use a mode-conditioning patch cable between the SFP and the fiber patch panel. The 1000BASE-LX SFP transceiver operates at 1310 nm over single-mode fiber (SMF). When connected to multimode fiber (MMF), the larger core diameter causes excessive modal dispersion, leading to CRC errors. A mode-conditioning patch cable (mode-conditioning patch cord) launches the laser off-center into the MMF core, reducing differential mode delay and restoring proper signal integrity. This is a known Cisco best practice for LX transceivers on MMF links.

Answer

Replace the SFP with a 1000BASE-SX transceiver

Answer

Configure the same VLAN on both switch interfaces

Answer

Replace the fiber cable with a single-mode fiber cable

Question 3

Which TWO statements accurately describe wireless LAN fundamentals for CCNA 200-301 v2.0? (Choose two.)

Accepted Answer

802.11ac operates only in the 5 GHz frequency band.. 802.11ac (Wi‑Fi 5) operates exclusively in the 5 GHz band, leveraging wider channels (up to 160 MHz) and reduced interference. Option D is correct: WPA3 introduces Simultaneous Authentication of Equals (SAE) for robust password‑based authentication, replacing the weaker WPA2 four‑way handshake. Option A is wrong: 802.11ax (Wi‑Fi 6) supports MU‑MIMO for both uplink and downlink, not only downlink. Option C is wrong: Overlapping channels in the 2.4 GHz band reduce throughput and are not used to maximize availability; instead, non‑overlapping channels (1, 6, 11) are recommended. Option E is wrong: A WLC is typically managed via a web GUI, SSH, or SNMP, not via its console port for routine operations; console access is used for initial setup or troubleshooting.

Answer

802.11ax uses MU‑MIMO only for downlink transmissions.

Answer

Overlapping channels in the 2.4 GHz band are used to maximize non-overlapping channel availability.

Answer

A wireless LAN controller (WLC) is typically managed via its console port for day-to-day operations.

Question 4

Which two statements accurately describe why BGP is often relevant at an Internet or multi-provider edge?

Accepted Answer

It is associated with routing between autonomous systems.. BGP is often relevant at the edge because it is associated with route exchange between autonomous systems and large external routing domains. In practical terms, this makes it a natural protocol to discuss where organizations connect to providers or exchange external reachability. It is not just another interior campus protocol.

The question is about conceptual fit, not deep BGP attribute tuning.

Answer

It is mainly used to replace STP on access switches.

Answer

It is required before DHCP relay can function.

Answer

It is the protocol used by CAPWAP for AP discovery.

Question 5

A router has routes to 172.20.0.0/16, 172.20.10.0/24, and 172.20.10.64/26. Which route is used for traffic to 172.20.10.70?

Accepted Answer

172.20.10.64/26. The /26 route is used because it is the most specific matching prefix. In practical terms, 172.20.10.70 falls inside the 172.20.10.64/26 range, so that route narrows the destination more precisely than the broader /24 and /16 routes. Longest-prefix match therefore selects the /26 entry.

This question is designed to reinforce that specificity comes first in route lookup. Broader routes remain useful, but they lose when a more exact route matches.

Answer

172.20.0.0/16

Answer

172.20.10.0/24

Answer

The default route

Question 6

You are connected to R1. R1 has OSPF configured on GigabitEthernet0/0 with network 10.0.0.0 0.0.0.3 area 1, ip ospf hello-interval 10, and ip ospf dead-interval 40. R2 has OSPF configured on its GigabitEthernet0/0 with network 10.0.0.0 0.0.0.3 area 0, ip ospf hello-interval 5, and ip ospf dead-interval 20. Correct these mismatches so that R1 and R2 become OSPF neighbors.

Accepted Answer

On R1, change the network statement to area 0 and set ip ospf hello-interval 5 and ip ospf dead-interval 20 under the interface.. The OSPF adjacency fails due to two mismatches. First, the area is mismatched: R1 uses area 1, R2 uses area 0 (both must be the same area, typically area 0). Second, the hello and dead timers are mismatched: R1 uses Hello 10/Dead 40, R2 uses Hello 5/Dead 20. To fix, on R1 change the network statement to area 0 and adjust timers to match R2 (or vice versa). The solution below changes R1's area to 0 and sets hello to 5 and dead to 20 to match R2.

Answer

On R2, change the network statement to area 1 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.

Answer

On R1, change the network statement to area 0 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.

Answer

On R2, change the network statement to area 0 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.

Question 7

A router has routes for 10.10.0.0/16, 10.10.20.0/24, and a default route. Which route is used for destination 10.10.20.55?

Accepted Answer

The 10.10.20.0/24 route. The destination matches multiple routes, but the /24 is the most specific match and wins by longest prefix match.

Answer

The 10.10.0.0/16 route

Answer

The default route

Answer

The router load-balances across all matching routes

Question 8

What problem do first-hop redundancy protocols such as HSRP solve?

Accepted Answer

They provide a backup default gateway for end hosts. First-hop redundancy protocols allow hosts to use a virtual default gateway that can remain available even if one physical router fails.

Answer

They prevent duplicate MAC addresses on a LAN

Answer

They replace spanning tree on switched networks

Answer

They encrypt traffic between users and the default gateway

Question 9

A router has a static route to 10.30.5.128/25, an OSPF route to 10.30.5.0/24, and a default route 0.0.0.0/0 in its routing table. Which route will the router use for destination 10.30.5.130?

Accepted Answer

The static route to 10.30.5.128/25. The router selects the route with the longest prefix match between the destination IP and the prefixes in the routing table. 10.30.5.130 matches both 10.30.5.0/24 (prefix length 24) and 10.30.5.128/25 (prefix length 25); the /25 is more specific and wins. Option D is wrong because 10.30.5.130 falls within the subnet range of 10.30.5.128/25 (hosts .129–.254), so a valid route does exist.

Answer

The OSPF route to 10.30.5.0/24

Answer

The default route

Answer

No route, because the destination is outside all prefixes shown.

Question 10

Which TWO statements accurately describe OSPFv3 configuration and verification for IPv6?

Accepted Answer

OSPFv3 uses IPv6 link-local addresses for neighbor discovery and next-hop addresses.. OSPFv3 uses IPv6 link-local addresses for neighbor discovery and next-hop addresses. Option C is correct because the 'ipv6 ospf area ' interface command enables OSPFv3 on that interface. Option B is incorrect: OSPFv3 does not use the 'network' command; instead, it relies on interface-level configuration. Option D is incorrect: 'ipv6 router ospf ' is a global configuration command to enter OSPFv3 router configuration mode, not an interface command. Option E is incorrect: 'show ipv6 ospf neighbor' displays neighbor adjacencies, not the link-state database; use 'show ipv6 ospf database' for that.

Answer

The 'network' command under 'ipv6 router ospf' is used to advertise subnets into OSPFv3.

Answer

The 'ipv6 router ospf <process-id>' command is used on an interface to enable OSPFv3.

Answer

The 'show ipv6 ospf neighbor' command displays the OSPFv3 link-state database.

Question 11

A controller API returns this data:

{
  "device": {
    "hostname": "Dist-1",
    "interfaces": [
      {"name": "Gig0/0", "status": "up"},
      {"name": "Gig0/1", "status": "down"}
    ]
  }
}

Which statement is correct?

Accepted Answer

The interfaces field is an array of objects. The interfaces field is an array of objects. The giveaway is the square brackets around the interface entries. In JSON, square brackets represent an array, and braces represent an object. Each interface entry inside that array has key-value pairs such as name and status, which makes each entry its own object. In plain language, the controller is returning a list of interface records for one device. The hostname field, by contrast, is a single value. This style of question appears in automation topics because the exam wants you to recognize common data structures used in controller APIs without requiring deep programming expertise. Understanding the difference between an object and an array is usually enough.

Answer

The response is XML because it contains nested elements

Answer

The hostname field is a list

Answer

The format shown is YAML

Question 12

A subnet must support 14 usable hosts. Which prefix is the smallest that meets the requirement?

Accepted Answer

/28. To support 14 usable hosts, the subnet must have 16 total addresses, because two are reserved for the network and broadcast addresses. In plain language, you need enough address slots so that after those two reserved entries are removed, 14 remain. A /28 provides exactly that: 16 total addresses and 14 usable addresses.

This is a classic minimum-subnet-size question because it tests whether you can work backward from host requirement to prefix length. A /29 would be too small, while a /27 would work but waste more addresses than necessary.

Answer

/29

Answer

/27

Answer

/26

Question 13

You are connected to SW1 via console. SW1 is a multilayer switch with SVIs for VLAN 10 (192.168.10.1/24) and VLAN 20 (192.168.20.1/24). Hosts in VLAN 10 and VLAN 20 need to communicate with each other. Currently, inter-VLAN routing is not working. You need to enable routing on SW1 and verify that the SVIs are operational.

Accepted Answer

Enable IP routing using the 'ip routing' global configuration command.. The 'ip routing' command enables Layer 3 routing on the multilayer switch, allowing SVIs to route between VLAN 10 and VLAN 20. Option B is unnecessary because directly connected SVIs do not require a routing protocol; routing protocols are only needed for routes learned from other routers, and 'ip routing' must still be enabled. Option C would require converting the physical interfaces to routed ports, which would break the existing Layer 2 VLAN topology and is not the intended solution. Option D provides an external router-on-a-stick solution but does not enable routing on SW1 itself, which is the required task. Therefore, only option A correctly enables inter-VLAN routing on SW1.

Answer

Configure a routing protocol such as OSPF or EIGRP on the SVIs.

Answer

Assign IP addresses to the physical interfaces connected to the hosts.

Answer

Create a trunk port and connect a router to perform router-on-a-stick.

Question 14

A switchport connected to another switch is configured as an access port by mistake. Which symptom is most likely in a multi-VLAN design?

Accepted Answer

Only one VLAN is likely to pass correctly, while other VLAN traffic across the link fails. The most likely symptom is that only one VLAN’s traffic works correctly across the link while traffic for other VLANs fails. In plain language, an access port belongs to one VLAN in normal switching behavior. If an inter-switch link that should carry multiple VLANs is accidentally configured as an access port, the network loses the ability to transport the other VLANs.

The physical link may stay up, which can make the problem seem subtle, but the logical role of the port is wrong.

Answer

The link negotiates as a trunk but drops all VLAN traffic

Answer

The switch generates excessive broadcasts on all VLANs

Answer

The switch stops learning MAC addresses entirely

Question 15

Why is PortFast typically enabled on switch ports connected to end devices?

Accepted Answer

To let end-device ports reach forwarding state more quickly. PortFast is enabled so access ports connected to end devices can move to forwarding more quickly instead of waiting through the normal spanning-tree listening and learning transitions. In plain language, it helps a user’s PC, printer, or similar endpoint start communicating sooner after the link comes up. That can reduce delays at startup and prevent certain device timeout problems.

PortFast is not intended as a loop-prevention mechanism by itself, and it should not normally be used carelessly on links to other switches. That is why it is commonly paired with BPDU Guard on edge ports. The correct answer is the one focused on faster transition for end-device access links rather than on unrelated routing or VLAN functions.

Answer

To make access ports participate in OSPF

Answer

To convert all access ports into trunks

Answer

To disable Ethernet addressing on PCs

Question 16

A user joins the employee SSID successfully and can browse internal resources, but VoIP over Wi-Fi calls fail only while roaming between floors. Which troubleshooting area is the strongest first focus?

Accepted Answer

Roaming behavior and RF transition quality between AP coverage areas. The strongest first focus is roaming and RF transition behavior between AP coverage areas. In practical terms, the user already proved that general WLAN access and internal reachability are working. The failure happens during movement and affects a time-sensitive application. That points to mobility-related behavior rather than basic SSID visibility or simple IP addressing.

This is a realistic wireless troubleshooting item because it narrows the fault domain from the symptom pattern instead of restarting from the basics.

Answer

Whether the SSID name is spelled correctly

Answer

Whether the branch router has PPP enabled

Answer

Whether the user has a static default route on the phone

Question 17

A network administrator connects an IP phone to interface Gi0/1 and a PC to the phone's PC port. Users report that the phone cannot register with the call manager and the PC does not obtain an IP address. The administrator verifies the configuration shown in the exhibit. What is the most likely cause of the problem?

Accepted Answer

The voice VLAN is not configured on the interface.. The voice VLAN is not configured on the interface. For an IP phone to communicate with the call manager, the switchport must be configured with a voice VLAN (e.g., 'switchport voice vlan 20') to separate voice traffic from data traffic. Without this command, the phone cannot tag its frames with the appropriate VLAN ID, preventing registration. Additionally, the PC connected to the phone's PC port relies on the phone to pass untagged data traffic, but without the voice VLAN, the phone may not properly negotiate or forward traffic, causing the PC to fail to obtain an IP address.

Answer

The switchport mode should be changed to trunk to allow tagged voice traffic.

Answer

The spanning-tree portfast command is blocking the port from forwarding.

Answer

The access VLAN 10 is incorrect for the data subnet.

Question 18

A network team wants to collect flow-level traffic statistics from routers to identify top talkers and bandwidth consumers. Which two statements about NetFlow are correct?

Accepted Answer

It summarizes traffic into flows instead of capturing every packet payload. NetFlow provides visibility into who is talking to whom, with what protocols and volume, making it valuable for capacity planning, troubleshooting, and security analysis.

Answer

It is primarily used to distribute time from an authoritative clock

Answer

It replaces routing protocols by advertising reachability information

Question 19

You are connected to a multilayer switch SW1 via console. SW1 has an IP phone and an access point connected to interfaces GigabitEthernet0/1 and GigabitEthernet0/2 respectively. Configure the access ports so that the IP phone receives a voice VLAN (VLAN 110) and PoE priority critical, and the access point receives PoE priority high. Verify your configuration using show interfaces switchport and show power inline.

Accepted Answer

interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 110
 power inline priority critical
!
interface GigabitEthernet0/2
 switchport mode access
 power inline priority high. The IP phone requires a voice VLAN configured with the switchport voice vlan command. PoE priority is set per interface using power inline priority. For the phone, the priority is critical; for the AP, it is high. Verification with show interfaces switchport confirms voice VLAN, and show power inline shows priority settings.

Answer

interface GigabitEthernet0/1
 switchport mode trunk
 switchport trunk allowed vlan 10,110
 power inline priority critical
!
interface GigabitEthernet0/2
 switchport mode access
 power inline priority high

Answer

interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 110
 switchport voice vlan 10
 power inline priority critical
!
interface GigabitEthernet0/2
 switchport mode access
 power inline priority high

Answer

interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 110
 power inline priority high
!
interface GigabitEthernet0/2
 switchport mode access
 power inline priority critical

Question 20

Refer to the exhibit. A network engineer expects SW1 to be the root bridge for VLAN 1, but the show spanning-tree vlan 1 output on SW2 shows that SW2 is the root. What is the most likely cause of this issue?

Accepted Answer

The trunk link between SW1 and SW2 is down.. If the trunk link between SW1 and SW2 is down, SW2 will not receive BPDUs from SW1. Without BPDUs, SW2 assumes it is the root bridge for VLAN 1 (since every switch defaults to root for its own VLANs). This explains why SW2's show spanning-tree output shows itself as root, even if SW1 has a lower bridge priority.

Answer

SW1 is configured with a priority of 32769 but has a higher MAC address than SW2.

Answer

Spanning tree is disabled on SW1 for VLAN 1.

Answer

SW1 has a bridge priority of 4096, but BPDU guard is configured on SW2's port to SW1, causing the port to be err-disabled.

CCNA Mock Exam 80 — 25 Questions

Exhibit

CCNA Mock Exam 80 — 25 Questions

Exhibit