rivate-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: 1-99,101-199,201-299,301-4094 Pruning VLANs Enabled: 100 Capture Mode Disabled Capture VLANs Allowed: ALL Protected: false Unknown unicast blocked: disabled Unknown multicast blocked: disabled Appliance trust: none You can add VLANs to the list of pruning-eligible VLANs with the add keyword, and remove them with the remove keyword: 3550-I0S(config-if); switchport trunk pruning vlan add 20-30 3550-I0S(config-if)# 3550-I0S(config-if)# switchport trunk pruning vlan remove 30 3550-IOS S(config-if)# Configuring VTP You can also specify that all VLANs except one or more that you list be made pruning-eligible with the switchport trunk pruning vlan except vlan-i id command. Remember to double-check your work with the show interface interface-id switchport command. Adding and removing VLANs can quickly get confusing, especially with IOS managing VTP pruning on an interface basis. CatOS CatOS gives you a nice warning about running VTP in the entire domain when you enable VTP pruning. Pruning is enabled with the set vtp pruning enable command: Switch1-CatOS# (enable) set vtp pruning enable This command will enable the pruning function in the entire management domain. All devices in the management domain should be pruning-capable before enabling. Do you want to continue (y/n) [n]? y VTP domain GAD-1 Lab modified Disabling pruning results in a similar prompt. To disable VTP pruning on CatOS, use the set vtp pruning disable command: Switch1-CatOS# (enable) set vtp pruning disable This command will disable the pruning function in the entire management domain. Do you want to continue (y/n) [n]? y VTP domain GAD-Lab modified Once pruning has been enabled, VLANs 2-1000 are eligible for pruning by default. To remove a VLAN from the list of eligible VLANs, use the clear vtp pruneeligible command. Unlike IOS, CatOS manages pruning-eligible VLANs on a switch level as opposed to an interface level: Switch1-CatOS# (enable) clear vtp pruneeligibl