Coder’s Eye

On my new dedicated server, I’ve been getting reports of mail bounces. Looking more closely at them, I found they said “451: Deferred sender callout cannot be verified.”

This is the result of an anti-spam measure that Cpanel enables by default for Exim. It took a while, but I finally found the well-written discussion and fix on Michael Brandonisio’s blog.

Basically, you simply add a white-list to exim for people who have misbehaving ISPs. The problem is really on their side, but telling them to fix their mailservers just doesn’t seem to work very well.

Technorati Tags: exim, cpanel