Block port 25 (outgoing mail/spam) for all machines except mail server using Watchguard System Manager and Firebox x1000

I recently had an infected system send out some spam. We've removed the system from the network and I believe that we've stopped the issue momentarily. My goal is to prevent this from happenning again. Obviously there are a lot things involved there.

One common, general piece of advice seems to be "block port 25 for all machines except your mail server". (The message id for the spam referenced the infected computer name, not the mail server, as our legitimate mail id's seem to).

So I'd like to configure (or make sure that we currenlty have) our Firebox 1000x to only allow mail to go out through our exchange server.

How do I do that? Where do I start?

My SMTP service is set to
Incoming: Enabled and Allowed From Any to 198.xxx.xxx.xxx->10.xxx.xxx.xxx (198.xxx being our external mx ip and 10.xxx being our internal Barracuda appliance)
Outgoing: Enabled and Allowed Any to Any

My filtered SMTP service is set to
Incoming: Denied From Any to Any
Outgoing: Enabled and Allowed From Any to Any

Thanks!

I relalize I have other issues to check, but this seems to be a starting place now that I've got the machine off the network and my virus scans are showing no signs of infection. (fingers crossed.)Start Free Trial