Posted by Vince Wadhwani on Aug 14, 2008

The other day one of my customers had the misfortune of getting thousands of Mail Delivery errors. The reason? Some spammer had used his email address in the 'from' field when sending out spam. The only thing you can really do to stop that sort of thing getting through is implementing Sender Policy Framework. What it does in a nutshell is provide recepient servers with some extra information to let them know if the mail they just got from example.com really came from example.com. If not, they can silently discard the mail and go on their way.

It's just one tool of many to combat spam. Unlike many others though, this one relies on others to play along and look for those SPF records. If you're running postfix, here's a post to implement SPF checks. For your own domain, the actual SPF record is held at the nameserver level so contact your mail server ISP after generating your records.

I'm curious to hear if anyone out there runs their own mail server and enforces SPF.