It really depends on the topology.

If both ACE & FWSM are in transparent mode the gateway will be the MSFC HSRP IP.

If ACE is in transparent mode and FWSM in routed mode the gateway will be FWSM.

If ACE is in routed mode the ACE will be the default gateway.

There are multiple options and it depends on your topology,

Syed Iftekhar Ahmed

Dear Iftekhar,

Thanks for your reply; if you can give me some more details that would be great,

1, Why should transparent be used over routed mode in fwsm/ACE.

2, It also looks like we deploy FWSM in routed mode then ACE should be in transparent mode.

3, What if we use IDSM-2, how can it will work on failover.

4, In case of FWSM be default gateway how would the failover works with all of the aboves modules installed in case of switch crash.

Thanks in advance.

Asim