How can you configure VLANs using the CLI?

2 Assigning ports

The next step to configure VLANs using the CLI is to assign the ports that you want to connect to each VLAN. To do this, you need to access the interface configuration mode of your network device and use the switchport mode access command to set the port as an access port, which means it can only belong to one VLAN. Then, use the switchport access vlan command followed by the VLAN ID to assign the port to the desired VLAN. For example, to assign port 1 to VLAN 10 and port 2 to VLAN 20, you would enter the following commands:

(config)#interface fastEthernet 0/1
(config-if)#switchport mode access
(config-if)#switchport access vlan 10
(config-if)#exit
(config)#interface fastEthernet 0/2
(config-if)#switchport mode access
(config-if)#switchport access vlan 20
(config-if)#exit        

To exit the interface configuration mode, use the exit command.

3 Verifying VLANs

The third step to configure VLANs using the CLI is to verify that the VLANs and the ports are configured correctly. To do this, you can use various show commands that display information about the VLANs and the ports on your network device. For instance, the show vlan command can help you view the existing VLANs and their names, while the show interfaces switchport command can provide information on the ports assigned to each VLAN and their status. To execute both commands, you would enter: #show vlan followed by #show interfaces switchport. This will enable you to check for errors or misconfigurations in order to ensure that the VLANs and ports are working as expected.

4 Troubleshooting VLANs

The final step to configure VLANs using the CLI is to troubleshoot any issues that may arise with the VLANs or the ports. To do this, you can use diagnostic commands such as the ping, traceroute, show interfaces, and show interfaces status err-disabled commands. For example, you can use the ping command followed by the IP address of the destination device to test connectivity between two devices on the same VLAN. To test connectivity between two devices on different VLANs, use the traceroute command followed by the IP address of the destination device. The show interfaces command followed by the interface name will allow you to view the status and statistics of an interface. Additionally, you can use the show interfaces status err-disabled command followed by the interface name to view errors and events related to an interface. These commands can help you identify and resolve problems related to connectivity, performance and errors that may affect your network device.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?