3Com Switch 8800 Family Firewall Module Configuration and Command Reference Guide

Firewall Configuration Commands 213
Use the undo security-vlan command to cancel the configuration.
By default, no VLAN is protected.
Example
# Set 10, 20 and 30 VLANs to be protected by SecBlade.
[3Com-secblade-newsec] security-vlan 10 20 30