CCNA Practice Test 37 — 15 Questions

Question 1

A branch router has two equal-cost static routes to the same destination network. Both routes are displayed in the output of the show ip route command, and pings from the router to both next-hop IP addresses succeed. Despite this, all traffic heading toward that destination is egressing only a single interface. The technician suspects Cisco Express Forwarding (CEF) is not performing load balancing as expected. What should the technician do next?

Accepted Answer

Verify the bandwidth configured on the outgoing interfaces using show interfaces or show running-config.. CEF load balancing can be influenced by the bandwidth values configured on the egress interfaces. Even when the routing table shows equal-cost paths, CEF may assign different load shares if the interfaces have mismatched bandwidth (e.g., if one interface has a manually lowered bandwidth). Verifying the interface bandwidth reveals whether an asymmetric configuration is causing CEF to favor one link over the other. This check targets the data‑plane forwarding behavior directly, before inspecting FIB entries or traffic counters.

Answer

Issue the show ip cef <destination> detail command to inspect the CEF FIB entry and verify both adjacencies are present.

Answer

Check the interface output rates with show interface to see if both interfaces are transmitting traffic.

Answer

Display the routing table again with show ip route to ensure both static routes are still installed.

Question 2

An EtherChannel uses LACP. One side is configured correctly, but the peer side has a different switchport mode on one of the member links. What is the most likely result?

Accepted Answer

The bundle may fail to form correctly because the member-link settings are inconsistent.. The most likely result is that the bundle will not form cleanly because EtherChannel requires member links to agree on important operational settings. In practical terms, LACP negotiation alone is not enough. The links also need compatible characteristics such as switchport mode, VLAN handling, speed, and duplex where relevant.

This is a common troubleshooting pattern. It tests whether you know that bundle membership depends on configuration consistency, not just on enabling LACP.

Answer

The switch automatically rewrites the peer configuration to match.

Answer

LACP converts the mismatched link into a routed interface automatically.

Answer

The mismatched link is placed in a spanning-tree blocking state.

Question 3

Which two statements accurately describe why organizations use separate employee and guest WLANs?

Accepted Answer

They allow different access policies and trust boundaries for different user groups.. Organizations use separate WLANs because different user groups usually require different trust levels, policies, and access rights. In practical terms, employees may need access to internal business systems, while guests usually need a more limited and isolated experience. Separate WLANs make that segmentation and policy enforcement easier.

This is a design and security decision, not just a naming preference.

Answer

They eliminate the need for wireless security.

Answer

They make all roaming problems disappear automatically.

Answer

They replace the need for VLANs or policy controls behind the scenes.

Question 4

Refer to the exhibit. A network engineer notices that a user connected to GigabitEthernet0/5 cannot access the network. The engineer issues the show port-security interface GigabitEthernet0/5 command. Based on the output, what is the most likely cause of the issue?

Accepted Answer

An unauthorized device with a different MAC address was connected, triggering a port-security violation and placing the port in an error-disabled state.. The exhibit shows the port status as 'Secure-shutdown', which indicates the port has been error-disabled due to a port-security violation. The 'Last Source Address' (aaaa.bbbb.cccc) is different from the sticky MAC address, and the violation count is 3, proving an unauthorized device attempted to connect, causing the shutdown.

Answer

The interface is administratively shut down.

Answer

The sticky MAC address feature is disabled, allowing any MAC address to cause a violation.

Answer

The maximum number of secure MAC addresses has been exceeded, causing the port to err-disable.

Question 5

A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?

Accepted Answer

The EIGRP route because it has the lower administrative distance. When identical prefixes are learned from different routing protocols, the router compares administrative distance first. EIGRP internal routes use AD 90, while OSPF uses AD 110.

Answer

The OSPF route because OSPF is link-state

Answer

The route with the lower metric value regardless of protocol

Answer

Both routes are always installed

Question 6

Which summary route best represents these four networks?
10.20.0.0/24
10.20.1.0/24
10.20.2.0/24
10.20.3.0/24

Accepted Answer

10.20.0.0/22. Four contiguous /24 networks starting at 10.20.0.0 summarize cleanly into 10.20.0.0/22. That block covers 10.20.0.0 through 10.20.3.255.

Answer

10.20.0.0/23

Answer

10.20.0.0/24

Answer

10.20.0.0/21

Question 7

A network engineer notices that after adding a new switch to the network, a different switch unexpectedly becomes the STP root bridge, disrupting all VLANs. The new switch has the default priority (32768) but has a lower MAC address than all existing switches. What is the most likely cause?

Accepted Answer

The existing root bridge has a bridge priority lower than the default value of 32768. In STP, bridge priority is the primary parameter for root election. If the existing root bridge has a bridge priority lower than the default 32768, it will have a lower Bridge ID regardless of its MAC address, so it remains the root. The new switch’s lower MAC would only win if all bridge priorities are equal (default). This explains why a different switch becomes root even though the new one has a lower MAC.

Answer

The new switch is running PVST+ while the existing switches use Rapid PVST+

Answer

Root Guard is enabled on the new switch’s uplink ports facing the existing root

Answer

The new switch was added with a bridge priority of 4096

Question 8

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?

Accepted Answer

One side is configured with LACP active and the other side is configured with mode 'on' (static).. The exhibit shows Po1(SU) with protocol LACP, but member interfaces Gi0/1 and Gi0/2 are in state (D) – down. This indicates LACP negotiation is failing. The most likely cause is that the remote side is using static mode 'on', which does not participate in LACP and sends no PDUs, so the local LACP active side cannot form a bundle, leaving the physical ports down while the port-channel logical interface remains up. This is confirmed by the combination of (D) flags and the LACP protocol designation without any bundled ports.

Answer

The local switch is configured with LACP passive while the remote switch is set to LACP active.

Answer

The remote switch is configured with PAgP desirable while the local switch uses LACP.

Answer

The port-channel member interfaces are configured as access ports, preventing LACP from negotiating.

Question 9

Refer to the exhibit. A network engineer configured an EtherChannel between SW1 and SW2 using LACP. After the configuration is applied, the Port-channel 1 interface remains in a down state and does not pass traffic. The engineer runs the show etherchannel detail command on SW1. Based on the output, what is the most likely cause of the problem?

Accepted Answer

The native VLAN is mismatched on member interface Gi0/2.. The show etherchannel detail output includes 'Native vlan mismatch: local 20, partner 1' for interface Gi0/2. This indicates that the native VLAN configured on Gi0/2 (local VLAN 20) does not match the native VLAN advertised by the partner switch (VLAN 1). This mismatch causes Gi0/2 to be suspended ('susp') and prevents it from joining the port-channel bundle, thereby keeping the EtherChannel down.

Answer

The load-balancing method on the port-channel is set incorrectly to src-dst-ip.

Answer

The interface Gi0/1 is administratively down.

Answer

Spanning Tree Protocol has placed the port-channel in a blocking state due to a loop.

Question 10

A router shows this output:

R1#show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
10.1.1.2          1   FULL/DR         00:00:34    192.168.12.2    GigabitEthernet0/0
10.1.1.3          1   2WAY/DROTHER    00:00:39    192.168.12.3    GigabitEthernet0/0

Which statement is correct?

Accepted Answer

This can be normal on a broadcast segment where DROTHER routers remain in 2-Way. On broadcast OSPF networks, full adjacency is typically formed with the DR and BDR. DROTHER routers can remain in the 2-Way state with one another and still be operating normally.

Answer

R1 has failed to form adjacency with 10.1.1.3

Answer

R1 has a duplicate router ID with 10.1.1.3

Answer

The interface is passive

Question 11

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.. SW2 shows itself as the root (Root ID and Bridge ID are identical, and the text 'This bridge is the root'), and there is no root port listed. In a stable spanning-tree topology, a non-root switch must have a root port to reach the root. The absence of any root port indicates that SW2 is not receiving superior BPDUs from SW1. The most likely cause is that the trunk link between SW1 and SW2 is down, preventing BPDU exchange.

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.

Question 12

Refer to the exhibit. A network engineer notices packet loss and sluggish application performance on a branch-office uplink. While troubleshooting, the engineer executes the show interfaces GigabitEthernet0/1 command on the router. Based on the output, what is the most likely cause of the performance issue?

Accepted Answer

An upstream device is sending traffic at a rate higher than this interface can transmit, causing the output queue to overflow.. The exhibit shows 12,450 output drops and an output queue that is completely full (40/40). The interface is up, operating at 100 Mb/s full-duplex, and shows zero input errors or CRC errors, ruling out physical layer corruption. The high output drops with a maxed-out output queue typically indicate that an upstream device is transmitting at a rate that exceeds the interface’s egress capacity, causing tail drops. This is a classic symptom of a speed mismatch where, for example, a distribution switch is forwarding traffic at 1 Gbps toward a 100 Mbps uplink.

Answer

The interface is experiencing excessive collisions due to a duplex mismatch.

Answer

The interface is receiving corrupted frames, indicated by the zero input errors on the interface.

Answer

The output queue is full because its size is too small, and increasing the queue depth will resolve the packet loss.

Question 13

A technician configures OSPF on R1 using the command network 10.0.0.0 0.0.0.255 area 0. R1's GigabitEthernet0/0 interface has IP address 10.0.0.1/30 and is included in the OSPF process. The technician confirms the interface is not passive using the show ip ospf interface GigabitEthernet0/0 command. However, R2 is not forming an OSPF adjacency with R1. What should the technician do next?

Accepted Answer

Verify the subnet mask configured on R2's connecting interface.. On broadcast multi-access networks like Ethernet, OSPF requires both neighbors to agree on the exact subnet mask; a mismatch causes the hello packets to be rejected. R1's interface is already confirmed to be in the correct area and not passive, so the next logical step is to check R2's interface configuration. Verifying the subnet mask on R2's connecting interface addresses a fundamental Layer 3 misconfiguration that would directly prevent adjacency formation, before investigating OSPF-specific parameters.

Answer

Check the OSPF hello and dead intervals on R1 and R2.

Answer

Verify the OSPF area ID configured on R2's interface.

Answer

Check whether R2's interface is configured as a passive interface.

Question 14

Refer to the exhibit. An engineer expects all traffic destined to the 10.10.10.0 network to be forwarded via 10.1.1.2. However, when testing connectivity to host 10.10.10.64, traffic is being sent to 10.2.2.2 instead. What is the most likely cause?

Accepted Answer

The router is using longest prefix matching; the /26 route is more specific, so traffic to 10.10.10.64 is forwarded via 10.2.2.2.. The show ip route output contains two static routes for destination 10.10.10.0, one with a /24 prefix and one with a /26 prefix. Both routes have an administrative distance of 1 and a metric of 0, as indicated by the [1/0] in the output. The router always performs longest prefix matching; a packet destined to 10.10.10.64 falls within the range 10.10.10.0 – 10.10.10.63 of the /26 route, making the /26 the more specific match. Therefore, traffic to 10.10.10.64 is forwarded via 10.2.2.2 despite the engineer's intent.

Answer

The static route to 10.10.10.0/24 has a higher administrative distance than the /26 route, making the /26 preferred.

Answer

The /26 static route was configured as a floating static route with an administrative distance of 5, overriding the /24 route.

Answer

The next-hop 10.1.1.2 for the /24 route is unreachable, causing the router to fall back to the /26 route.

Question 15

A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?

Accepted Answer

The OSPF route, because 110 is lower than 150. The route with the lower administrative distance is installed. A static route configured with a higher AD becomes a floating static route and remains as a backup until the preferred route disappears.

Answer

The static route, because static routes always win

Answer

Both routes, because administrative distances are different

Answer

Neither route, because the static route is floating