There seems to be several zombies out there randomly trying to send mail to my user mail boxes. They seem to be virus ladden messages. The source of the traffic can be blocked but I would rather use the sender on my SMTP security server. I get the following log entries: agent mail server orig_from <> orig_to jose@xxxx.xxx How can I block these. I am using CP 4.0. I cannot upgrade at this point. I can block by IP address but this seems a bit futule... Can I block vacant sender domains?