Is it possible to use a secondary IP Address on the FWSM.
Customer wishes to migrate VLAN 1 behind the FWSM.
description "LEGACY VLANS"
ip address 192.168.2.1 255.255.255.0 secondary
ip address 192.168.1.1 255.255.255.0
The FWSM does not have a secondary ip address.
You can hack it to proxy for that ip by doing
static(interface_name,interface_name) 192.168.2.1 192.168.2.1
But that would just make the FWSM to proxy arp for that ip and receive the packets.
If your goal is for these packets to be destined to the FWSM itself for management it won't work.
If it is for through traffic it could make it work.
I hope it helps.