I cannot post configs of the router in question, I apologize for that. We are having an issue that when we apply an ACL to an interface it begins blocking traffic for what seems like no reason. The ACL only has one line permit ip any any. When it is applied in the inbound direction on an outside interface weird things begin to happen. An open RDP session to a server on the other side of the router is dropped, but the SSH connection to the router stays up. A mail marshall server we have goes through all normal smtp messages with the distant end MTA, but fails when the email payload is actually attempted to pass. When the ACL is removed, everything flows as normal again. I'm sorry for the vagueness of this question, attached is a rudimentary diagram.