show vlan brief

VLANs known to the switch and which access ports are in them.

switching

What it does

Lists VLANs in the local database with their member access ports. Trunk ports do not appear against a VLAN here — trunk membership is a separate question.

Per vendor

PlatformCommand
Cisco IOSshow vlan brief
Cisco NX-OSshow vlan brief
Aruba AOS-CXshow vlan
MikroTik RouterOS/interface bridge vlan print
Juniper JunOSshow vlans

Useful variations

  • One VLANshow vlan id 20
  • What a trunk actually carriesshow interfaces trunk

Pitfalls

The misreadings that actually cost people time.

  • A VLAN missing here while configured on a trunk means it was never created — traffic is dropped silently.
  • Ports in a trunk do not show under their VLANs; use `show interfaces trunk`.
  • On VTP clients the database comes from the server, so local edits may be refused or overwritten.

Related

show interfaces statusshow spanning-tree