We are currently running a Pix 515E 6.3(5), no failover mode. I am getting alot of drops on the outside interface on SMTP port. The error is 106015 Deny TCP (no connection) from IP_addr/port to IP_addr/port flags. I have researched the error and it appears that this is a malformed smtp packet that is getting discarded. Is this usual behaviour or is this something I should be looking at ?
I am dropping this traffic from a wide range of public IP's.
Any help would be appreciated.