Cisco WS-C2950-24 Configuration Manual page 273

Chapter 8 Configuring VLANs
Command
Step 1 configure terminal
Step 2
interface interface_id
Step 3
switchport mode trunk
Step 4
switchport trunk allowed vlan
remove vlan-list
Step 5
end
Step 6
show interface interface-id
switchport allowed-vlan
Step 7
copy running-config
startup-config
78-6511-05
Beginning in privileged EXEC mode, follow these steps to modify the allowed list
of a ISL or 802.1Q trunk:
Purpose
Enter global configuration mode.
Enter interface configuration mode and the port to be
added to the VLAN.
Configure VLAN membership mode for trunks.
Define the VLANs that are not allowed to transmit and
receive on the port.
The vlan-list parameter is a range of VLAN IDs Separate
nonconsecutive VLAN IDs with a comma and no spaces;
use a hyphen to designate a range of IDs. Valid IDs are
from 2 to 1001.
Return to privileged EXEC.
Verify your entries.
Save the configuration.
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
How VLAN Trunks Work
8-41