It seems that a lot of my mail (especially short messages) is getting marked as spam. I should first say that I'm not on any blacklists and my volume is very low, and I have SPF and DomainKeys configured. I just sent a few test messages to another email account so I could take a look at the headers as they are received by others. I noticed the following in the X-Spam-Status header: FH_HELO_ENDS_DOT=3.02 It appears that my spam score is being raised because my HELO ends in a dot. I was under the assumption that HELO should contain your FQDN-- which, by definition, ends in a dot. This makes short messages VERY likely to be blocked by spam filters, including my own. There's nothing on the SpamAssassin wiki about this (that just happens to be the only rule that doesn't have a page created for it), and I've noticed a few other cPanel/WHM servers are doing this as well. I tried specifying a HELO name in /etc/heloname and switching on the relevant option in Exim, but the issue persists.