Oct 11, 2007 · One way to boost network security is to use Cisco's Port Security feature to lock down switch ports. Learn the basics of port security, and find out how to configure this feature. Jun 24, 2019 · The native VLAN association on the trunk port was mistakenly changed on the switch to VLAN 6. This means only devices on VLAN 6 could reach the NetScreen device. The trunk port on the switch should have a native VLAN set to 1. This is specific to Cisco switches.
My testing below shows "switchp trunk allow vlan remove 20" removes vlan 20 from the trunk totally. While "switchport trunk pruning vlan remove 20" or "add 20" doesn't seem to do anything. SW2(config-if) #do show int trunk . Port Mode Encapsulation Status Native vlan. Gi3/3 on 802.1q trunking 99