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Cisco Switches


To show the VLANs and port assignments: show vlan brief

Trunk ports

If you're not sure which interfaces are set to trunk or not, try:

show interfaces trunk module 1

Show which VLANs are allowed on the trunk port:

show interfaces gigabitEthernet 1/0/24 trunk

If you want to specify which VLANs are allowed on the trunk port:

Note: If there is not a cable plugged in to the trunk port, it will say “Vlans allowed: none”

int gi1/0/24
switchport trunk allowed vlan 1,100

But if you don't specify, then it will allow all VLANs. (I think… but this is not confirmed)


Find which switch ports have devices online

show interfaces status | i connected

Find which port a MAC is on

eg if you want to find and monitor a specific printer:

swi01#show mac address-table address 1C:7D:22:0D:8C:B7

        Mac Address Table


Vlan Mac Address Type Ports
—- ———– ——– —–
100 1c7d.220d.8cb7 DYNAMIC Gi1/0/3

kb/cisco_switches.1506403540.txt.gz · Last modified: 2017/09/26 14:55 by Dan Mundy