I built a basic test laboratory with a Palo Alto Networks PA-200 firewall and two Cisco Catalyst 2950 switches in order to test the Spanning Tree Protocol (STP) for achieving Layer 2 redundancy for the physical connections to/from the firewall. This post lists the configurations, “show spanning-tree” outputs from the switches and a few other outputs after several tests. Not all tests ran without any problems so I think there must be something wrong with my configurations, the test sequences, with the STP process, or with the MAC address tables. Maybe some readers have similar experiences?
[UPDATE] Problem solved! I missed the layer 2 zones. Description at the bottom [/UPDATE]