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
Other verification commands include:
■ show running-config interface interface-num—Use the
following 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 interface-num vlan vlan-num—
Use the following 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
Total Mac Addresses for this criterion: 1
■ show interfaces interface-num switchport—Use the following to see
detailed information about the port configuration, such as entries in the
Administrative Mode and Access Mode 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