Viewing Your VLAN Trunking Protocol (VTP) Settings - dummies

Viewing Your VLAN Trunking Protocol (VTP) Settings

By Edward Tetz

VLAN Trunking Protocol (VTP) changes the VLAN database of your switch; therefore, you will not see VTP settings in your running configuration. This is sometimes confusing because whenever you make changes in Global Configuration mode, the changes show up in your running configuration — except your VTP settings. To see the VTP settings, use the show command. Passwords are listed with the password command.

Switch1#show vtp ?
  counters  VTP statistics
  password  VTP password
  status    VTP domain status

The most useful option probably is status, which shows you the VTP configuration — minus the password — for your switch. Note that you see the revision number here, as well as the mode and domain name:

Switch1#show vtp status
VTP Version                     : 2
Configuration Revision          : 1
Maximum VLANs supported locally : 128
Number of existing VLANs        : 11
VTP Operating Mode              : Server
VTP Domain Name                 :
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0xBC 0x8C 0xD6 0xE4 0x2F 0xA4 0x5D 0x28
Configuration last modified by at 3-20-11 22:27:26
Local updater ID is on interface Vl1 (lowest numbered VLAN interface found)

counters is a little less useful — unless you are not seeing any of the VLAN updates from neighboring switches. In that case, counters is very useful because it shows you the advertisements that you sent and received. If you are not receiving these, check the Trunk settings.

The last thing you see in counters is the pruning information, which again will be useful if you have VTP pruning enabled because it shows where the pruning occurs on the network.

Switch1#configure terminal
Switch1#show vtp counters
VTP statistics:
Summary advertisements received    : 6
Subset advertisements received     : 1
Request advertisements received    : 0
Summary advertisements transmitted : 7
Subset advertisements transmitted  : 2
Request advertisements transmitted : 0
Number of config revision errors   : 5
Number of config digest errors     : 0
Number of V1 summary errors        : 0
VTP pruning statistics:
Trunk            Join Transmitted Join Received    Summary advts received from
                                                   non-pruning-capable device
---------------- ---------------- ---------------- ---------------------------
Fa0/1               0                0                0