A some-time client of mine has a mail/web server hosted at a hosting company. This server is running Debian - fairly stock config - and exim4. I was tasked, some time ago, with configuring this environment appropriately for their webapp - a primary function of which is sending mail.
Well, being unfamiliar with Debian at the time, I did my best, hacked the changes necessary into their existing config and got it working. Some time later, when they wanted SMTP authentication, I did some reading up, and found out the following:
( Cut for boring )So, I took this opportunity to configure the mail setup properly, using the split config. Took me a few hours one evening to get it all sorted properly. Then, thinking maybe they might see that exim4.conf was missing and think everything was broken, I put the following file, named README.IMPORTANT in the /etc/exim4.conf directory:
( Cut for boring )Their external firewall was set to forward from a high port, externally, to port 25 on the machine, so that SMTP was accessible externally but on a non-standard port.
Everything was rocking along fine.
So, yesterday I get a mail stating that the mail system is broken, and can I please investigate. A cursory investigation shows me that everything is working on the machine, but the external port is closed. I send a mail back to this effect.
This morning, I notice that mail is working again, and think nothing much more of it.
Some time later, I get ANOTHER mail, reporting that mail is again broken.
So, apparently, their tech has checked the machine in response to a support request, found it not listening on the high port (which it shouldn't, it listens on 25), surmised therefore that everything is broken (which it isn't) and has put back a copy of exim4.conf, overriding all my changes.
*HEADDESK* *HEADDESK*
So now I have to wait for him to finish dicking about before I can check just how badly it's broken and fix it. *sigh*
ETA: I should mention that they put the port forward in place at our request, so they bloody well should have known about it.