Refer to the exhibit. A network administrator configures R1 for inter-VLAN routing between VLAN 10 and VLAN 20. However, the devices in VLAN 10 and VLAN 20 cannot communicate. Based on the configuration in the exhibit, what is a possible cause for the problem?

Last Updated: May 6, 2026
IT Exam Items Repository › Category: CCNA › Refer to the exhibit. A network administrator configures R1 for inter-VLAN routing between VLAN 10 and VLAN 20. However, the devices in VLAN 10 and VLAN 20 cannot communicate. Based on the configuration in the exhibit, what is a possible cause for the problem?

Refer to the exhibit. A network administrator configures R1 for inter-VLAN routing between VLAN 10 and VLAN 20. However, the devices in VLAN 10 and VLAN 20 cannot communicate. Based on the configuration in the exhibit, what is a possible cause for the problem?

  • The port Gi0/0 should be configured as trunk port.
  • The encapsulation is misconfigured on a subinterface.
  • A no shutdown command should be added in each subinterface configuration.
  • The command interface gigabitEthernet 0/0.1 is wrong.

Explanation: In a router-on-a-stick configuration, each subinterface must be assigned to the correct VLAN using the encapsulation dot1q vlan-id command. The exhibit shows two errors: first, "dot10" is an incorrect protocol name (it should be dot1q), and second, the second subinterface is assigned to VLAN 2 (encapsulation dot10 2) instead of the intended VLAN 20 associated with the 192.168.20.0/24 subnet.

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