ccess Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Administrative Native VLAN tagging: enabled Voice VLAN: none Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk Native VLAN tagging: enabled Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk associations: none Administrative private-vlar trunk mappings: none Operational private-vlan: none Trunking VLANs Enabled: ALL Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL Protected: false Unknown unicast blocked: disabled Unknown multicast blocked: disabled Appliance trust: none You configure which VLANs are eligible for pruning at the interface level in IOS. Use the command switchport trunk pruning vlan on each trunking interface on the switch where pruning is desired: 3750- (config-if)#switchpor trunk pruning vlan ? WORD VLAN IDs of the allowed VLANs when this port is in trunking mode add VLANs to the current list except all VLANs except the following no VLANs remove remove VLANs from the current list All VLANs are eligible for pruning by default. If you configure VLAN 100 to be eligible for pruning, IOS considers this to mean only VLAN 100 should be eligible: Configuring VTP 3750-I0S(config-if)#switchport trunk pruning vlan 100 No message is displayed indicating that you have just disabled pruning for VLANs 2- 99 and 101-1001. You have to look at the interface again to see: 3750-IOS#sho int g1/0/15 switchport I inc Pruning Pruning VLANs Enabled: 100 You can add VLANs to the list of pruning-eligible VLANs with the add keyword and remove them with the remove keyword: 3750-I0S(config-if)#switchport trunk pruning vlan add 20-30 3750-I0S(config-if)#switchport trunk pruning vlan remove 30 You can also specify that all VLANs except one or more that you list be made eligible for pruning with the switchport trunk p