The joys of running one's own mail server

Minor issue. We changed IP addresses at work recently. A larger block of public facing IPs for more functionality. And in doing so, we updated almost everything correctly. Yes, almost everything. Almost. Everything. The one, minor … trivial … thing we left unchanged … broke our support site sending reply emails correctly. They were rejected about 50% of the time, as they came in on the wrong port/ip. So for the last week we’ve been sending extra emails. And tonight I got pissed off enough that I actually fixed it. Joy.