VTP Configuration Facts

VTP Configuration Facts

The following table lists common VTP commands.

Use...	To...
Switch(config)#vtp mode server|client|transparent	Configure the VTP mode of the switch. The default mode is server.
Switch(config)#vtp domain WORD	Configure VTP domain of the switch. The default domain name is <null> (blank). All switches must be configured with the same domain name. A new VTP client switch (with a blank domain name) will automatically set its domain name based on the first VTP advertisement it receives. A switch in transparent mode will not automatically set its domain name.
Switch(config)#vtp password WORD	Configure VTP password of the switch. When a password is used, all switches in the same domain must use the same password. You must manually configure the VTP password on each switch.
Switch(config)#vtp pruning	Reduce broadcast traffic by forwarding the messages only through switch trunks which belong to a particular VLAN ID. Enabling or disabling VTP pruning on a server enables or disables it on all devices in the domain.
Switch#show vtp status	View the current VTP configuration of the switch.
Switch#show vtp password	View the current VTP password of the switch.

Be aware of the following when troubleshooting the VTP configuration:

• If you add a switch to the network with a higher revision number, the VLAN configuration on that switch will update (modify) the existing VLAN configuration on all other switches in the domain. This is true even if the switch you add is a client. Client switches pass their configuration information on to other switches. This information can be used to update server or client switches with lower revision numbers.
• If you add a switch to the network with a lower revision number, the switch's configuration will be modified to match the configuration currently used on the network. This is true even if the switch you add is a server.
• To prevent disruptions to the existing configuration when adding new switches, reset the revision number on all new switches before adding them to the network. The revision number resets to 0 each time you:
  • Change the domain name.
  • Change the VTP mode to transparent.

Before adding a switch back into the network, change the domain name or the mode to transparent, then change it back to its original setting.

• Be sure to place switches in the same domain adjacent to each other through trunk links. If you insert a switch with a different domain name between two switches, VTP information will not be passed through the new switch. To correct this problem, use one of the following solutions:
  • Modify the domain name on the new switch to match the existing switches.
  • Move the new switch so that switches in the same domain are connected directly together.

Note: Once set, you cannot completely remove a domain name. In other words, once you have configured a VTP domain name, you can only change the name, you cannot remove it completely.

 

 

Credit: Testout 640-802 CCNA Notes