A PIX-515 running v7.2(1) is continuously dropping packets because of exceeding the embryonic counter limit which is currently set to 500.
The sessions dropped are connection requests initiated from outside to internal clients which are prohibited by the ruleset (ACL). Why is the PIX dropping connection requests with the "embryonic session limit" feature and not with the ACL deny statement ? Unfortunately the PIX is also dropping legitimate TCP connections. What could be the reason for that and is there a way to influence this misbehaviour ?