When you configure your mail publishing solution, make sure that your configuration does not allow for mail relay. If you do, you'll notice a lot of traffic on your external interface from spammers using your site as a relay.
Here's helpful post on testing your relay configuration:
From: Akron, OH, USA
Exchange 4.0 & 5.0 do not allow selective mail relay...You'll need to upgrade if you have one of these connected to the internet.
Exchange 5.5 is not configured out of the box to block relay, but you can alter your relay settings via the registry, or if you have Exchange 5.5 sp2 or higher you can change your relay settings from the Exchange Administrator program.
Exchange 2000 blocks relay by default
Newer versions of sendmail also block relay by default
If you have external users who MUST send across your mail server, set your relay to allow relay to users who successfully authenticate (AUTH)
Another workaround is to set your external users to send through their ISP's SMTP server, and recieve mail from your server (POP3). Normally if you are on your ISP's network you'll be able to send through their servers without supplying your credentials.
Hey Tom when i click on the link to test my email server it just opens up a command promt, but it displays to fast for me to read what it says, is this by design. CAn you tell me how to set it up so i can read the info?