Linux – Prevent outgoing spam

emaileximlinuxspamassassinweb-hosting

What are some ways to prevent spam from leaving your servers should a hosting account get compromised?

Have a bunch of clients on a server with cpanel but wondering if there was a way to just prevent a chance if an account was compromised.

  • When I meant compromised I meant, a client signs up or a client account and gets hacked and his account is used for spam.

  • couldn't you setup some type of filter/blacklist terms in exim or spamassassin which would block/stop mail going out if it matched that?

Best Answer

Don't get compromised. Seriously.

  • Monitor your traffic. You'll understand what's normal and be able to recognize abnormal traffic.

  • Shut down unnecessary daemons. If the server isn't supposed to send mail, don't run sendmail or postfix.

  • Restrict SSH access and/or assign SSH a non-standard port (e.g. don't use the default port 22). If you need to use port 22, then augment with a service like DenyHosts to track and stop inbound SSH bot authentication attempts.

  • Use or enforce strong passwords for yourself and your customers.

Oh, and this: Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?