100-150 Question 190
Select 3A network administrator has configured a switch with multiple VLANs to segment traffic. After connecting a new device to the switch, users report that they cannot communicate with the device, even though it is powered on and connected to the correct VLAN. Upon investigation, the administrator finds that the switch's MAC address table does not contain an entry for the device. Which of the following steps could resolve the issue?
- A
Verify that the device is configured with the correct VLAN ID.
- B
Ensure that MAC address filtering is not blocking the device's MAC address.
- C
Check if the port connecting the device is set to trunk mode.
- D
Confirm that the switch port is configured as an access port for the correct VLAN.
- E
Inspect the switch’s MAC address table aging time settings.
Show answer and explanation
Correct answers: A, B, D
Explanation
The issue arises because the new device's MAC address is not visible in the switch's MAC address table. This could be caused by incorrect VLAN configuration on the device, MAC address filtering blocking the device, or the switch port not being properly configured as an access port for the correct VLAN. By verifying these settings, the administrator can ensure proper communication between the device and other devices in the same VLAN.
- A. Correct.
If the device is configured with the wrong VLAN ID, it will not be able to communicate with devices in the correct VLAN. Verifying the VLAN configuration is essential.
- B. Correct.
MAC address filtering can block specific devices from being recognized by the switch. Ensuring that the device's MAC address is not blocked can resolve the issue.
- C. Incorrect.
Trunk mode is used for inter-VLAN communication between switches, not for connecting end devices. This is unlikely to be the cause of the issue.
- D. Correct.
The switch port must be configured as an access port and assigned to the correct VLAN for the device to communicate properly.
- E. Incorrect.
The MAC address table aging time determines how long a MAC address remains in the table, but it does not prevent new devices from being added to the table.