CCNA Network Infrastructure and Connectivity Practice Test 7 — 15 Questions

Question 1

You are troubleshooting a wired client connectivity issue on VLAN 10. PC1 (192.168.10.50/24) cannot reach the internet. The gateway is R1's subinterface G0/0.10 at 192.168.10.1. R1 has a default route to ISP router 203.0.113.1. From PC1, ping 192.168.10.1 fails, but ipconfig shows correct IP. R1's physical interface GigabitEthernet0/0 is administratively down. Fix the problem on R1 so that PC1 can ping its default gateway.

Accepted Answer

Enable the physical interface GigabitEthernet0/0 with 'no shutdown'.. PC1 has correct IP and cannot ping gateway 192.168.10.1. Because R1's physical interface GigabitEthernet0/0 is administratively down, subinterface G0/0.10 cannot process traffic. Enable the physical interface with 'no shutdown'. The default route is already present. The correct answer is A.

Answer

Configure 'no shutdown' on subinterface G0/0.10 and add a static route for 192.168.10.0/24 pointing to the ISP.

Answer

Change the IP address of subinterface G0/0.10 to 192.168.10.254 and add a default route via 203.0.113.1.

Answer

Enable VLAN 10 on the switch and configure trunking between the switch and R1.

Question 2

You are troubleshooting a wired client connectivity issue. A user on VLAN 10 (subnet 192.168.10.0/24) reports that they cannot reach the internet. The client PC is connected to switch SW1, which is connected to router R1. You have console access to the client PC and R1. Identify and fix the misconfiguration so that the client can ping the internet host 203.0.113.1.

Accepted Answer

Configure R1 as a DHCP server for VLAN 10, exclude the router's VLAN 10 IP (e.g., 192.168.10.1), provide the default gateway 192.168.10.1 to clients via DHCP, and add a default route on R1 via the ISP next-hop IP (e.g., 203.0.113.254).. The client PC likely has an APIPA address because no DHCP server is available for VLAN 10. R1 should be configured as a DHCP server for VLAN 10 and must provide the default gateway 192.168.10.1, which is on the same subnet as the client. R1 also needs a default route toward the ISP next-hop IP, not directly to the internet host 203.0.113.1. A default route must point to a next-hop router, not the final destination.

Answer

Change the client's IP address to a static IP in the 192.168.10.0/24 subnet and set the default gateway to 203.0.113.1.

Answer

Enable DHCP snooping on SW1 and configure the client port as trusted.

Answer

Configure a static route on the client PC to 203.0.113.1 via the router's IP.

Question 3

You are troubleshooting connectivity between R1 and R2. R1's GigabitEthernet0/0 interface is configured with a static IP of 10.0.0.1/30 but cannot ping its neighbor R2 at 10.0.0.2/30. R1 is using a 1000BASE-T SFP module to connect to a 1000BASE-LX/LH SFP on R2, but the link is down. Diagnose and resolve the issue by ensuring the correct SFP is used for the 2 km fiber run.

Accepted Answer

Replace the 1000BASE-T SFP with a 1000BASE-LX/LH SFP. No manual speed or duplex configuration is needed.. The link is down because 1000BASE-T (copper) and 1000BASE-LX/LH (fiber) are physically incompatible. Replace the SFP with a 1000BASE-LX/LH SFP. Gigabit fiber SFPs automatically operate at 1000 Mbps full duplex; no manual speed, duplex, or auto-negotiation commands are needed or applicable on the fiber port.

Answer

Keep the 1000BASE-T SFP and configure 'no negotiation auto', 'speed 1000', and 'duplex full' on R1.

Answer

Replace the 1000BASE-T SFP with a 1000BASE-LX/LH SFP, then configure 'speed 1000' and 'duplex full' on R1 without disabling auto-negotiation.

Answer

Replace the 1000BASE-T SFP with a 1000BASE-LX/LH SFP, then configure 'no negotiation auto' on R1 without setting speed and duplex.

Question 4

You are connected to R1 via the console. R1 and R2 are directly connected via their GigabitEthernet0/0 interfaces. Configure R1's G0/0 for 100 Mbps full-duplex operation. Then, diagnose and fix an auto-negotiation failure that prevents the link from coming up. Finally, replace the existing 1000BASE-T SFP with a 1000BASE-LX SFP to support a new 5 km fiber run. Ensure the link is up and working.

Accepted Answer

Configure speed 100 and duplex full on G0/0, then no shutdown. After the link is up, issue shutdown on the interface before physically swapping the SFP. Then remove the 1000BASE-T SFP and insert the 1000BASE-LX SFP, configure the interface with speed auto and duplex auto, issue no shutdown, and finally verify the link state.. After configuring speed 100 and duplex full on R1's G0/0 and issuing no shutdown, the initial link comes up. For the SFP replacement, issue shutdown on the interface before physically removing the 1000BASE-T SFP to prevent damage. After inserting the 1000BASE-LX SFP, configure speed auto and duplex auto so the interface renegotiates with the new optics, issue no shutdown, and verify the link is up.

Answer

Configure speed 100 and duplex full on G0/0, then no shutdown. After the link is up, remove the 1000BASE-T SFP and insert the 1000BASE-LX SFP; the interface will automatically detect the new SFP and adjust speed/duplex.

Answer

Configure speed 100 and duplex full on G0/0, then no shutdown. After the link is up, remove the 1000BASE-T SFP and insert the 1000BASE-LX SFP, then configure the interface with speed 1000 and duplex full to match the new SFP.

Answer

Configure speed 100 and duplex full on G0/0, then no shutdown. After the link is up, remove the 1000BASE-T SFP and insert the 1000BASE-LX SFP, then configure the interface with speed 100 and duplex full to maintain consistency.

Question 5

You are connected to R1. Configure the G0/0 interface to match the speed (100 Mbps) and duplex (full) of the connected switch port, then diagnose and fix an auto-negotiation failure that has caused excessive CRC errors. Finally, select and replace the SFP module on G0/0 with one that supports a 5 km fiber link, using the correct cable type.

Accepted Answer

Set speed 100, duplex full; replace SFP with 100BASE-LX; use single-mode fiber (SMF).. To match the connected switch port, hardcode speed 100 and duplex full on R1's G0/0. CRC errors indicate a speed/duplex mismatch; explicitly setting both ends to 100/full rather than auto-negotiation fixes the mismatch. For a 5 km single-mode fiber link at 100 Mbps, use a 100BASE-LX SFP (100BASE-LX10) with SMF. A 1000BASE-LX SFP is gigabit and cannot operate at speed 100; 1000BASE-SX uses multimode fiber; setting speed 1000 or leaving auto-negotiation does not match the given switch port.

Answer

Set speed 100, duplex half; replace SFP with 1000BASE-SX; use multimode fiber (MMF).

Answer

Set speed 1000, duplex full; replace SFP with 1000BASE-LX; use single-mode fiber (SMF).

Answer

Set no speed, no duplex (auto); replace SFP with 1000BASE-LX; use single-mode fiber (SMF).

Question 6

You are connected to the console of R1. The network administrator reports that hosts in VLAN 10 cannot reach the server at 192.168.1.100. R1 is the default gateway for VLAN 10 via subinterface G0/0.10. The link between R1 and the switch SW1 appears to be up, but pings fail. Your task is to identify and resolve the issue.

Accepted Answer

Check the duplex and speed settings on the physical interface G0/0 of R1 and the corresponding switchport on SW1; they may be mismatched.. The most likely cause of the connectivity issue is a duplex/speed mismatch on the physical link between R1 and SW1. If the physical interface is up but pings fail, and the subinterface is configured correctly, a duplex mismatch can cause intermittent or failed connectivity due to collisions and errors. Checking and correcting the duplex and speed settings on both ends resolves the issue.

Answer

Check the interface status on R1's G0/0.10 subinterface; it may be administratively down.

Answer

Verify that the VLAN 10 SVI on SW1 has an IP address in the correct subnet.

Answer

Ensure that the native VLAN on the trunk between R1 and SW1 is VLAN 1.

Question 7

You are connected to the console of R1. The network uses IPv6 and you need to configure an IPv6 address on interface G0/0 using the EUI-64 format. The subnet is 2001:db8:acad:1::/64. The interface MAC address is 0011.2233.4455. After configuration, verify that the full IPv6 address is correct.

Accepted Answer

ipv6 address 2001:db8:acad:1:0211:22ff:fe33:4455/64. The EUI-64 method inserts FFFE in the middle of the MAC and flips the U/L bit. With the given MAC, the resulting interface ID is 0211:22FF:FE33:4455, forming the full IPv6 address.

Answer

ipv6 address 2001:db8:acad:1:0011:22ff:fe33:4455/64

Answer

ipv6 address 2001:db8:acad:1:0011:2233:4455/64

Answer

ipv6 address 2001:db8:acad:1:0211:2233:4455/64

Question 8

You are connected to the console of R1. The network administrator reports that hosts on VLAN 10 cannot ping the default gateway (192.168.10.1). R1's GigabitEthernet0/1 is connected to a switch with trunk port allowing VLAN 10 and 20. The interface configuration on R1 appears correct, but the VLAN 10 interface is not operational.

Accepted Answer

The physical interface GigabitEthernet0/1 was administratively down.. The VLAN 10 interface is not operational because the physical interface GigabitEthernet0/1 is administratively down. Router-on-a-stick subinterfaces depend on the physical interface being up/up; if the physical interface is shut down, all subinterfaces remain down regardless of their configuration. The correct fix is to issue 'no shutdown' on GigabitEthernet0/1.

Answer

The VLAN 10 subinterface was configured with the wrong encapsulation dot1q VLAN ID.

Answer

The switch port connected to R1 was not configured as a trunk.

Answer

The VLAN 10 subinterface was missing the 'no shutdown' command.

Question 9

You are connected to the console of R1. The network uses IPv6 with EUI-64. R1's GigabitEthernet0/0 has MAC address 0011.2233.4455. You need to configure an IPv6 address on this interface using the prefix 2001:db8:1:1::/64 with EUI-64, and ensure the interface is operational.

Accepted Answer

ipv6 address 2001:db8:1:1::/64 eui-64. Uses the correct syntax 'ipv6 address 2001:db8:1:1::/64 eui-64', which configures the prefix and derives the interface ID automatically from the MAC address via EUI-64. Option A is invalid because specifying the full 128-bit address with the eui-64 keyword is not allowed; the eui-64 keyword requires only a prefix. Option C omits the eui-64 keyword, so it configures a static address without using EUI-64, which would not match the requirement to use EUI-64. Option D appends the MAC address after the eui-64 keyword, which is invalid syntax; the eui-64 keyword does not accept an explicit MAC address.

Answer

ipv6 address 2001:db8:1:1:0011:22ff:fe33:4455/64 eui-64

Answer

ipv6 address 2001:db8:1:1:0211:22ff:fe33:4455/64

Answer

ipv6 address 2001:db8:acad:1::/64 eui-64

Question 10

You are connected to the console of SW1. The network administrator reports that SW1 cannot discover neighbouring devices using CDP. SW1 is connected to R1 via GigabitEthernet0/1. CDP is globally enabled, but still no neighbours are shown.

Accepted Answer

Enable CDP on interface GigabitEthernet0/1 with the command 'cdp enable'.. CDP can be enabled or disabled globally and per interface. Even when CDP is globally enabled with 'cdp run', it can be disabled on a specific interface with 'no cdp enable'. To restore neighbor discovery on GigabitEthernet0/1, the administrator must enable CDP on that interface using 'cdp enable'. This is the precise fix for the symptom described.

Answer

Enable CDP globally with the command 'cdp run'.

Answer

Use the command 'lldp run' to enable LLDP as an alternative.

Answer

Check the physical cable and interface status on GigabitEthernet0/1.

Question 11

You are connected to the console of R1. R1 is a new router that needs to be configured for remote management. The network administrator wants to enable SSH for secure access with a local user 'admin' and password 'cisco123'. The router already has an IP address 192.168.1.1/24 on GigabitEthernet0/0 and the interface is up.

Accepted Answer

Enable SSH by configuring a hostname, domain name, generating RSA keys, creating local user 'admin' with password 'cisco123', and configuring VTY lines with 'login local' and 'transport input ssh'. No further configuration is needed.. To enable SSH with local authentication, the router requires a unique hostname, an IP domain name, RSA keys, a local username/password, and VTY lines configured with both 'transport input ssh' and 'login local'. Option D correctly includes all these elements. Option A is incorrect because it only mentions 'SSH transport' but does not explicitly include the 'login local' command on the VTY lines, which is necessary to use the local username database for authentication. Option B is missing the domain name, which is required for RSA key generation. Option C uses Telnet transport, which is unsecure and not SSH. Therefore, D is the correct answer.

Answer

Enable SSH by configuring a hostname, domain name, generating RSA keys, creating local user 'admin' with password 'cisco123', and configuring VTY lines for SSH transport.

Answer

Enable SSH by configuring a hostname, generating RSA keys, creating local user 'admin' with password 'cisco123', and configuring VTY lines for SSH transport. No domain name is needed.

Answer

Enable SSH by configuring a hostname, domain name, generating RSA keys, creating local user 'admin' with password 'cisco123', and configuring VTY lines for Telnet transport.

Question 12

You are connected to the console of R1. The network administrator reports that users cannot communicate with the server at 192.168.2.10. R1 is connected to R2 via a serial link (S0/0/0) with IP 10.0.0.1/30 on R1 and 10.0.0.2/30 on R2. The network uses OSPF for routing. You suspect an interface issue on the serial link.

Accepted Answer

Use the show interfaces serial0/0/0 command to verify the interface status and check for encapsulation mismatch.. The show interfaces serial0/0/0 command displays the line and protocol status, encapsulation type, and error counters for the serial interface. Since the suspicion is an interface issue on the serial link, this command directly reveals whether the interface is up/up, has an encapsulation mismatch (HDLC vs PPP), or shows input/output errors that would prevent OSPF adjacency formation.

Answer

Use the show ip route command to verify that the route to 192.168.2.0/24 is present in the routing table.

Answer

Use the ping 10.0.0.2 command to test Layer 3 connectivity to the neighbor router.

Answer

Use the show running-config interface serial0/0/0 command to check the configuration of the serial interface.

Question 13

You are connected to the console of R1. The network uses IPv6 with EUI-64. R1's GigabitEthernet0/0 has MAC address 0011.2233.4455. You need to configure an IPv6 global unicast address on this interface using EUI-64 format, based on the prefix 2001:db8:acad:1::/64. The interface is currently configured with an IPv4 address only.

Accepted Answer

R1(config-if)# ipv6 address 2001:db8:acad:1:0211:22ff:fe33:4455/64. The EUI-64 process splits the MAC address 0011.2233.4455 into two halves: 0011.22 and 33.4455. It inserts FFFE in between to get 0011.22FFFE33.4455, then flips the seventh bit (U/L bit) of the first byte from 00 to 02, resulting in 0211.22FF.FE33.4455. The full IPv6 address is 2001:db8:acad:1:0211:22ff:fe33:4455/64. Option A correctly uses this manually computed address. Options B and C have incorrect interface IDs. Option D uses the 'eui-64' keyword which automatically derives the interface ID from the MAC, but the question expects the static address, as indicated by the provided options. Therefore, option A is the correct answer.

Answer

R1(config-if)# ipv6 address 2001:db8:acad:1:0011:22ff:fe33:4455/64

Answer

R1(config-if)# ipv6 address 2001:db8:acad:1:0211:2233:4455:5566/64

Answer

R1(config-if)# ipv6 address 2001:db8:acad:1::/64 eui-64

Question 14

You are connected to the console of R1. The network uses IPv6 with EUI-64. R1's GigabitEthernet0/0 interface has MAC address 001e.4a7b.9c0d. You need to configure an IPv6 address on this interface using EUI-64, with the subnet 2001:db8:abcd:1::/64.

Accepted Answer

ipv6 address 2001:db8:abcd:1::/64 eui-64. The `eui-64` keyword instructs the router to automatically generate the interface identifier portion of the IPv6 address from the interface's MAC address using the EUI-64 process. Without this keyword, the address `2001:db8:abcd:1::/64` would be configured as a static address with an all-zeros interface ID, which is invalid for a host address. The `eui-64` option is the only one that correctly combines the specified prefix with an auto-generated host portion.

Answer

ipv6 address 2001:db8:abcd:1::/64

Answer

ipv6 address 2001:db8:abcd:1::/64 link-local

Answer

ipv6 enable

Question 15

You are connected via the console to R1, a Cisco ISR 4331 router. The network administrator reports that the link between R1's GigabitEthernet0/0 and a switch is experiencing high error rates and intermittent connectivity. Upon inspection, you notice that the interface is configured with speed 1000 and duplex full. The switch port is set to auto-negotiate. Your task is to resolve the duplex mismatch by configuring the router interface to match the switch's settings.

Accepted Answer

Configure the router interface with 'no speed' and 'no duplex' to restore defaults, then set 'speed auto' and 'duplex auto'.. The duplex mismatch was caused by manually forcing speed and duplex on the router while the switch was set to auto-negotiate. Changing the router to auto-negotiate allows both sides to negotiate the best duplex (full duplex) and speed, eliminating errors.

Answer

Configure the router interface with 'speed 1000' and 'duplex full'.

Answer

Configure the router interface with 'no speed' and 'no duplex' to restore defaults, then set 'speed 1000' and 'duplex full'.

Answer

Configure the router interface with 'no speed' and 'no duplex' to restore defaults, then set 'speed 1000' and 'duplex half'.

CCNA Network Infrastructure and Connectivity Practice Test 7 — 15 Questions

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CCNA Network Infrastructure and Connectivity Practice Test 7 — 15 Questions

Exhibit