Verifying VLAN Configuration 

To see a list of all the VLANs and the ports assigned to them, use the command show vlan. To narrow down the information displayed, you can use these keywords after the command:

brief, id, vlan‐number, or name 

vlan‐name: ASW# show vlan brief 

VLAN Name Status Ports 

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/10,Fa0/11,Fa0/12 

20 VLAN0020 active Fa0/5,Fa0/6,Fa0/7 

21 VLAN0021 active Fa0/8,Fa0/9 

1002 fddi‐default active 

1003 trcrf‐default active 

1004 fddinet‐default active 

1005 trbrf‐default active 

show running‐config interface interface no: 

Use to verify the VLAN membership of the port: 

ASW# show run interface fa0/5 

Building configuration… 

Current configuration 64 bytes interface FastEthernet 0/5 switchport access vlan 20 switchport mode access

show mac address‐table interface interfaceno. vlan vlanno: 

Use to view MAC addresses learned through that port for the specified VLAN: 

ASW# show mac address‐table interface fa0/1 

Mac Address Table    
Vlan Mac Address Type Ports‐
1 0030.b656.7c3d DYNAMIC Fa0/1

show interfaces interface‐no. switchport: 

Use to see detailed information about the port configuration, such as entries in the Administrative Mode and Access Mode V VLAN fields: 

ASW# show interfaces fa0/1 switchport Name: Fa0/1 

Switchport: Enabled 

Administrative Mode: dynamic desirable Operational Mode: static access 

Administrative Trunking Encapsulation: negotiate Operational Trunking Encapsulation: native Negotiation of Trunking: On 

Access Mode VLAN: 1 (default) 

Trunking Native Mode VLAN: 1 (default) 

Trunking VLANs Enabled: ALL 

Pruning VLANs Enabled: 2‐1001 Protected: false 

Unknown unicast blocked: false Unknown multicast blocked: false Broadcast Suppression Level: 100

Multicast Suppression Level: 100 

Unicast Suppression Level: 100


Creating Ethernet VLANs on Catalyst Switches