I have 2 Pix 525 .it works as Active/Standby .in my case the Active is the secondry and the standby is the primary Pix. we use Failover cable and stateful failover together .
the Sync/Failover is working fine but
When i configured subinterfaces on the inside of the Active pix(Secondry) and issued the write memory command on the Active ,the Syncronization failed and both of them become active .
When i removed the subinterfaces config and configured ACL or anything else the Failover process works fine.
Any Help Pls?