Administrator Guide

Layer 2 Switching Commands 829
Syntax
switchport general forbidden vlan {add vlan-list | remove vlan-list }
• add vlan-list — List of valid VLAN IDs to add to the forbidden list.
Separate nonconsecutive VLAN IDs with a comma and no spaces. Use a
hyphen to designate a range of IDs.
•
remove vlan-list — List of valid VLAN IDs to remove from the forbidden
list. Separate nonconsecutive VLAN IDs with a comma and no spaces. Use
a hyphen to designate a range of IDs.
Default Configuration
All VLANs allowed.
Command Mode
Interface Configuration (Ethernet and port channel) mode
User Guidelines
This configuration only applies to ports configured in general mode. It is
possible to configure the general mode VLAN membership of a port while the
port is in access or trunk mode. Doing so does not change the VLAN
membership of the port until it is configured to be in general mode.
Example
The following example forbids adding VLAN numbers 234 through 256 to
port 1/0/8.
console(config)#interface gigabitethernet 1/0/8
console(config-if-Gi1/0/8)#switchport general forbidden vlan add 234-256
switchport general acceptable-frame-type
tagged-only
Use the switchport general acceptable-frame-type tagged-only command in
Interface Configuration mode to discard untagged frames at ingress. To
enable untagged frames at ingress, use the no form of this command.
2CSNXXX_SWUM204.book Page 829 Monday, January 25, 2016 1:25 PM