Spanning Tree Protocol STP packets dropped in Vwire mode

Symptoms

Spanning tree (STP) packets are dropped when going through the firewall when configured as V-Wire causing erratic behavior on devices adjacent to the firewall.

Cause

By default, a pair of V-Wire interfaces allows untagged traffic (no 802.1q headers).  The cause may be the STP packets being dropped are part of a VLAN.

Resolution

In the V-Wire configuration, enter the tags that should be allowed through the V-Wire interfaces. For most scenarios, a list of all the vlans is necessary.

owner: sdurga