PIX - BGP Advanced Protocol Inspection
When passing BGP traffic through a PIX you will need to configure the PIX to disable random sequence numbers to prevent MD5 Digest mismatches on either router.
Please Note : Below presumes you all ready have a policy map defined with the name of global_policy and this has already been assigned to your device using the service-policy command.
access-list BGP-MD5-ACL permit tcp host [BGP ROUTER IP] host [BGP ROUTER IP] eq bgp
tcp-options range 19 19 allow
match access-list BGP-MD5-ACL
set connection random-sequence-number disable
set connection advanced-options BGP-MD5