CCNA Practice Test 40 — 15 Questions

Question 1

You are connected to R1 via console. PC1 is connected to R1's GigabitEthernet0/1 interface and is configured with a static IP address. PC1 cannot reach the internet (203.0.113.1). Identify and resolve the connectivity issue. Configure R1 to restore full connectivity for PC1.

Accepted Answer

Configure NAT overload on R1: define ACL 1 to permit 192.168.1.0 0.0.0.255, set GigabitEthernet0/0 as outside and GigabitEthernet0/1 as inside, and apply ip nat inside source list 1 interface GigabitEthernet0/0 overload.. PC1 has a default gateway of 192.168.1.1, which is correct, but R1 is not performing NAT. R1 can reach the internet (203.0.113.1) but PC1 cannot because R1 drops packets from PC1 destined to the internet without source NAT. The fix is to configure NAT overload (PAT) on R1: define an ACL to match PC1's subnet, configure the inside and outside interfaces, and enable NAT on the outside interface. This will translate PC1's private IP to R1's public IP.

Answer

Configure a static route on R1: ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0 203.0.113.1.

Answer

Change PC1's default gateway to 203.0.113.1.

Answer

Enable IP routing on R1 and configure OSPF.

Question 2

A switch shows this output from the "show interfaces trunk" command:

Gi0/1    on        802.1q    trunking    1
Gi0/2    auto      802.1q    not-trunking  1

Which statement is correct?

Accepted Answer

Gi0/1 is trunking, and Gi0/2 is waiting for DTP negotiation. Gi0/1 is already operating as an 802.1Q trunk. Gi0/2 is in dynamic auto mode, which waits for the other side to actively negotiate trunking.

Answer

Gi0/1 is an access port in VLAN 1

Answer

Gi0/2 is forced to trunk mode

Answer

Neither interface can carry tagged traffic

Question 3

Drag and drop the following steps into the correct order to configure a single-area OSPFv2 network on two Cisco routers (R1 and R2) and observe the neighbor state transitions from Down to Full.

Accepted Answer

Configure OSPF process and router-id on R1, then add the network; repeat on R2; ensure interfaces are up; finally verify neighbor states.. First configure OSPF process and router-id on R1, then add the network; repeat on R2; ensure interfaces are up; finally verify neighbor states to see the full transition sequence.

Answer

Configure OSPF process and router-id on R1, then ensure interfaces are up; repeat on R2; add the network; finally verify neighbor states.

Answer

Ensure interfaces are up on both routers, then configure OSPF process and router-id on R1; add the network; repeat on R2; finally verify neighbor states.

Answer

Configure OSPF process and router-id on R1, then add the network; ensure interfaces are up; repeat on R2; finally verify neighbor states.

Question 4

You are connected to Multilayer Switch SW1. Configure LACP EtherChannel between SW1 and SW2 using ports GigabitEthernet0/1 and GigabitEthernet0/2. Ensure the channel is formed and active. The current configuration has mismatched VLAN assignments and speed/duplex settings preventing the channel from coming up. Verify the channel state using 'show etherchannel summary'.

Accepted Answer

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20,30.. The EtherChannel is down because the two member ports on SW1 have inconsistent configurations. GigabitEthernet0/1 is set to speed 1000 and duplex full with allowed VLANs 10,20, while GigabitEthernet0/2 is set to speed 100 and duplex half with allowed VLAN 30. LACP requires all member ports to have identical speed, duplex, and VLAN allowed lists. To fix, on SW1 configure both Gi0/1 and Gi0/2 with the same speed (1000), duplex (full), and trunk allowed VLANs (10,20,30). The Port-channel interface already has the correct allowed VLANs. After correction, 'show etherchannel summary' should show both ports as bundled (P).

Answer

Configure both Gi0/1 and Gi0/2 with speed 100, duplex half, and switchport trunk allowed vlan 30.

Answer

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport trunk allowed vlan 10,20.

Answer

Configure both Gi0/1 and Gi0/2 with speed 1000, duplex full, and switchport mode access.

Question 5

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

Accepted Answer

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

Answer

The OSPF /16 route, because dynamic routes override static routes learned later.

Answer

Both routes equally, because they point to the same major network.

Answer

Neither route, because overlapping routes are invalid.

Question 6

Refer to the exhibit. A network engineer is investigating intermittent connectivity complaints on a gigabit uplink between two distribution switches. The engineer runs the show interfaces GigabitEthernet0/0 command on one of the switches. Based on the output, what is the most likely cause of the errors?

Accepted Answer

A damaged or faulty cable is causing excessive CRC errors.. The output shows a high number of CRC errors and runts, which typically indicate a Layer 1 physical-layer issue such as a damaged or faulty cable. CRC errors occur when frames fail the cyclic redundancy check due to signal degradation, noise, or physical damage to the cabling. On a gigabit uplink, this is the most likely cause of intermittent connectivity.

Answer

The interface is configured with an incorrect encapsulation type.

Answer

A duplex mismatch exists between the connected devices.

Answer

The interface is assigned to the wrong VLAN.

Question 7

Port security is enabled with a maximum of 2 MAC addresses, but a third device connected through a small hub causes a violation. Which result is expected in restrict mode?

Accepted Answer

Frames from the unknown MAC are dropped and the violation is counted. In restrict mode, the switch drops frames from unknown source MAC addresses and increments the violation counter, but the port stays up. That is less disruptive than shutdown mode.

Answer

The port goes immediately to err-disabled state

Answer

The switch learns the third MAC after 30 seconds automatically

Answer

STP blocks the port until the MAC table ages out

Question 8

In a REST-style API, which method is most commonly associated with retrieving information?

Accepted Answer

GET. GET is the method most commonly associated with retrieving information. In practical terms, when a client wants to read state, inventory, or configuration details from an API endpoint without modifying the resource, GET is the expected choice.

This is a core automation vocabulary question and works well as an easier confidence-building item.

Answer

DELETE

Answer

POST

Answer

PUT

Question 9

You are connected to R1. Configure OSPFv2 on R1 and R2 so that they form a full adjacency and can exchange routes. The current configuration has mismatched hello/dead timers blocking the adjacency. Adjust only the necessary settings on R1 to match R2's OSPF timers.

Accepted Answer

Configure 'ip ospf hello-interval 5' and 'ip ospf dead-interval 20' on R1's GigabitEthernet0/0 interface.. The adjacency between R1 and R2 is not forming because the OSPF hello and dead timers are mismatched. R1 has default timers (Hello 10, Dead 40) while R2 has custom timers (Hello 5, Dead 20). To form an adjacency, OSPF timers must match on both ends. On R1, you need to configure the OSPF interface timers to match R2 by issuing 'ip ospf hello-interval 5' and 'ip ospf dead-interval 20' on interface GigabitEthernet0/0. After applying these commands, the adjacency should come up.

Answer

Configure 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40' on R2's interface to match R1's default timers.

Answer

Configure 'ip ospf hello-interval 5' on R1's GigabitEthernet0/0 interface only; the dead interval will adjust automatically.

Answer

Configure 'ip ospf dead-interval 20' on R1's GigabitEthernet0/0 interface only; the hello interval will adjust automatically.

Question 10

A named standard ACL is configured to permit only the 192.168.30.0/24 subnet, but users from 192.168.31.0/24 are still passing traffic. What is the most likely reason?

Accepted Answer

The ACL is probably applied in the wrong place or direction for the traffic flow. Standard ACLs filter traffic based solely on the source IP address. If users from 192.168.31.0/24 are still passing traffic despite the ACL permitting only 192.168.30.0/24, the most likely reason is that the ACL is applied in the wrong place or direction. For example, if the ACL is applied inbound on an interface where traffic from 192.168.31.0/24 does not enter, or outbound on an interface where the traffic does not exit, the filter will not affect the intended flow. The implicit deny statement denies all unmatched traffic, so if the ACL were correctly placed, traffic from 192.168.31.0/24 would be denied.

Answer

Standard ACLs cannot match source addresses

Answer

Named ACLs ignore wildcard masks

Answer

The deny any line must appear before the permit

Question 11

You are troubleshooting a link between R1 (G0/0) and R2 (G0/0). The link is up but experiencing packet loss. You suspect an interface speed/duplex mismatch or SFP issue. Configure R1's interface to match the correct speed and duplex, and replace the SFP module if necessary to support a required distance of 40 km over single-mode fiber.

Accepted Answer

Remove manual speed/duplex settings, enable auto-negotiation, and replace the SFP with a long-reach module (e.g., 1000BASE-ZX) that supports 40 km over single-mode fiber.. The link is experiencing packet loss, likely due to a speed/duplex mismatch between the manually configured interface and the peer (which may use auto-negotiation) and/or an SFP module that cannot support the required 40 km distance over single-mode fiber. To resolve both potential issues, remove any manual speed and duplex settings to restore default auto-negotiation (using 'no speed' and 'no duplex'), and replace the SFP with a module rated for 40 km or more on SMF, such as a 1000BASE-ZX (or 1000BASE-EX) transceiver. Standard 1000BASE-LX/LH only reaches up to 10 km on SMF, so it is insufficient for this scenario.

Answer

Change the duplex to full and speed to 1000 Mbps manually, and keep the existing SFP.

Answer

Keep the manual speed/duplex settings but replace the SFP with a 1000BASE-SX module.

Answer

Enable auto-negotiation on both ends but keep the existing SFP.

Question 12

Two switches are configured to form an EtherChannel, but the bundle never comes up. Which explanation best describes this scenario?

Accepted Answer

LACP active on one side is incompatible with mode on on the other side.. One side is using LACP active mode and the other side is forcing a static channel-group with mode on. Those modes are not compatible. LACP needs active or passive on both sides, while PAgP uses desirable or auto, and static mode on expects a manual bundle on the other side.

Answer

The switches are using different native VLANs.

Answer

Both sides must use PAgP desirable mode.

Answer

The interfaces must be configured as routed ports first.

Question 13

You are connected to R1. The link between R1's GigabitEthernet0/0 and R2's GigabitEthernet0/0 should operate at 1 Gbps full duplex, but the interface is showing errors and only negotiating at 100 Mbps half duplex. Diagnose and fix the fault, then verify the link is stable at the correct speed and duplex.

Accepted Answer

Remove the manual speed and duplex settings on R1's GigabitEthernet0/0 with 'no speed' and 'no duplex' to allow auto-negotiation.. The interface was manually configured with 'duplex half' and 'speed 100', which forced the link to 100 Mbps half duplex, causing CRC errors due to duplex mismatch. The correct fix is to remove these manual settings and allow auto-negotiation, or explicitly set both sides to 'speed 1000' and 'duplex full'. Since the remote side (R2) is set to auto (default), the simplest correction is to use 'no duplex' and 'no speed' on R1 to re-enable auto-negotiation. After the commands are applied, the interface should show 'Full-duplex, 1000Mb/s' and CRC errors should stop incrementing.

Answer

Change the duplex setting to 'full' and speed to '1000' on R1's GigabitEthernet0/0.

Answer

Replace the cable between R1 and R2 with a crossover cable.

Answer

Configure R2's GigabitEthernet0/0 with 'speed 100' and 'duplex half' to match R1's settings.

Question 14

An ACL is intended to block Telnet from 10.1.1.0/24 to router VTY access while still allowing SSH from the same subnet. Which statement best explains why an extended ACL is appropriate here?

Accepted Answer

Because the ACL must distinguish traffic by protocol or destination port, not just by source address.. An extended ACL is appropriate because the requirement is based not only on source address but also on the specific protocol and application port involved. In practical terms, the policy must distinguish Telnet from SSH even though both originate from the same source subnet. A standard ACL would be too limited because it mainly matches only on source address.

This is the kind of requirement that shows why extended ACLs exist. They allow more granular traffic control by matching protocol and destination details, not just who sent the packet.

Answer

Because standard ACLs can match destination TCP ports just as well.

Answer

Because extended ACLs are required for every router login policy regardless of criteria.

Answer

Because SSH and Telnet always use the same port number.

Question 15

A two-switch EtherChannel bundle is configured with LACP. One side uses active mode on both member links, while the other side uses passive mode on both member links. What is the result?

Accepted Answer

The bundle forms successfully. LACP forms a channel when at least one side actively sends negotiation frames. Active-to-passive works. Passive-to-passive would fail, but that is not the case here.

Answer

The links remain individual because both sides must use active

Answer

The bundle forms only if PAgP is also enabled

Answer

The channel comes up but forwards only one VLAN

CCNA Practice Test 40 — 15 Questions

Exhibit

CCNA Practice Test 40 — 15 Questions

Exhibit