I'm really a total newbie to this, so excuse the basicness (?) of the question.

I have a default installation of Windows Server 2003, and I want to test an e-mailing application.

  1. What's the process for setting up an SMTP server on that box? Does Windows Server 2003 provide one, or can I install a free one? Which one?
  2. I want to test my app in terms of delivering the e-mail to the SMTP server, but I don't actually need the e-mails to go out. Is there a way to have the SMTP server behave as it normally would, except just don't send out the e-mails?



  1. As Matt alluded to, use the "Manage Your Server" screen to add the SMTP role as per these instructions.
  2. You could use Windows Firewall on that server to block all outgoing traffic over port 25. Better yet, block all outbound port 25 traffic from your server's IP address at the gateway's firewall. This keeps you from crippling the server's network connection completely.

You could read up a bit on SMTP security on Windows Server 2003 with the following Microsoft KB Article 324285 (sorry, you'll have to find that one on your own; Server Fault only allows new users to post one URL per post). That article shows that you can grant or deny access to the SMTP virtual server based on IP addresses. This could be yet another alternative way of restricting mail flow to only those few places that you want to allow.

  • @nonapeptide: cool, thanks, went with blocking port 25. seemed to be the simplest solution! cheers
    – andy
    Jun 17 '09 at 23:17
  • yeah i agree, this solution was much simpler than the one I presented. Well done.
    – Matt
    Jun 18 '09 at 15:39

You can setup the Windows Server 2003 with the Mail Server role. It comes with Windows, so in a sense it is free (as in you already paid for it).

If you give the server a bad gateway ip then it cannot send any emails, and you can check everything you need to on your LAN.

Being new be very careful. I would check heavily into security for Windows Server 2003 especially in regards to email. This could make an excellent vector of attack against you.

  • thanks matt, what should I watch out for in terms of security. And, what would be a bad gateway ip? cheers
    – andy
    Jun 17 '09 at 1:10
  • @matt: hey matt, I have the Default SMTP Virtual Server running and sending e-mails. Now, where is the gateway set up so it doesn't send the e-mail? cheers
    – andy
    Jun 17 '09 at 1:28
  • I would just use a bad gateway on the actually ip address for the server. My guess is the mail server would use it to send emails to the "outside world". So in Network connections, have your IP be good and subnet be good, but make the gateway be something like This will keep any emails from leaving your LAN because when it goes to the gateway it won't be able to route them correctly to the outside.
    – Matt
    Jun 17 '09 at 2:17
  • hey I just thought of something else. You can also set your subnet mask to be which tells your computer, all traffic regardless of where it is headed should stay on the LAN and no go out to the gateway ip. Keep in mind this will break all outgoing traffic from the server not just email. (i.e. http)
    – Matt
    Jun 17 '09 at 2:24
  • Security wise, I would ask around on serverfault. Maybe make a new question. I know just enough about smtp security to know I should not give out too much advice, other than be aware of it.
    – Matt
    Jun 17 '09 at 2:27

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