100-150 Question 192
Select 3A network administrator is troubleshooting connectivity issues in a network with multiple VLANs. They discover that a host in VLAN 10 cannot communicate with a host in VLAN 20, but both hosts are connected to the same switch. The administrator suspects an issue with the MAC address table or VLAN configuration. Which of the following steps should the administrator take to resolve the issue?
- A
Verify that the switch has the correct VLAN assignments for the ports connected to the hosts.
- B
Check the MAC address table to ensure the MAC addresses of both hosts are present and associated with the correct VLANs.
- C
Enable MAC address filtering to allow only approved MAC addresses to communicate between VLANs.
- D
Ensure that inter-VLAN routing is configured if communication between VLAN 10 and VLAN 20 is required.
- E
Disable VLAN tagging on all switch ports to simplify communication across VLANs.
Show answer and explanation
Correct answers: A, B, D
Explanation
To troubleshoot communication issues between hosts in different VLANs, the administrator should first verify VLAN assignments for the relevant switch ports and ensure the MAC address table entries are correct. If communication between VLANs is required, inter-VLAN routing must also be configured. Enabling MAC address filtering and disabling VLAN tagging are not appropriate solutions in this scenario as they do not address the root cause of the issue.
- A. Correct.
This step is necessary to ensure that the switch ports connected to the hosts are correctly assigned to VLAN 10 and VLAN 20, as incorrect VLAN assignments can cause communication issues.
- B. Correct.
Checking the MAC address table helps verify that the switch has learned the MAC addresses of the hosts and associated them with the correct VLANs. A missing or incorrect entry in the MAC address table could indicate a configuration or connectivity issue.
- C. Incorrect.
Enabling MAC address filtering is not relevant to resolving communication issues between VLANs. It is typically used for security purposes to restrict devices based on their MAC addresses.
- D. Correct.
Inter-VLAN routing is required for communication between different VLANs. Without it, hosts in VLAN 10 and VLAN 20 cannot communicate, even if the VLANs are correctly configured.
- E. Incorrect.
Disabling VLAN tagging is not a valid solution and would disrupt the VLAN configuration, potentially causing more issues in the network.