Mail server no longer accepting incoming mail

Question

First off, let me just say that yes, I broke it. This is on an iMac G4 with Server 10.4.11.
So here's the problem. I am by no means a qualified Server Administrator, but since I am a relatively knowledgeable computer geek, my boss plugged me into this position while my department is slow. I've been tasked with figuring out a few nagging problems with slow mail delivery, among other things.
I did some serious Googling on the issue of slow mail delivery, messages getting stuck in queue, etc. I determined that the issue was with spam filtering and anti-virus. Following some great documentation from osx.topicdesk.com, I updated and configured clamav, amavisd, and spamassassin. Miraculously, this actually solved the problem, and everything was working great.
Until today. Today I noticed a log entry that reverse DNS lookup of the server's IP (192.168.1.1) had failed. Googled again and found some info on setting up DNS on the server, which I did.
There was a secondary goal for doing this. We are a small company that hosts our own email and a tiny web server on a machine at our corporate office. Our remote locations have always been able to get email from the server via POP3 using the FQDN mailman.mycompany.com, which has a public IP address. Our router is configured to forward traffic to that IP to the private IP 192.168.1.1. However, all users at the corporate office had to be set up to use server IP 192.168.1.1 to get their mail because there was no way to resolve the FQDN into an IP that was visible on the private network. Or maybe there was/is, but I don't know about it. Anyway, we have a couple mobile users that work at multiple locations. They are set up to use the server's FQDN, but every time they come to our corporate office, they'd have to change their mail setup if they wanted to get mail, because once they're behind the router, the FQDN doesn't work. I think that makes sense.
The Server is also the DHCP server for this site. Prior to this morning, it was distributing our ISP's DNS IPs. Once I'd set up DNS on our Server, I changed it to distribute its own IP as the primary DNS server, and per someone's post, I modified named.conf to include our ISP's DNS IPs. The server name I set up is 'server' and the domain is 'mycompany.com'. I also set up an alias of 'mailman' and set it as a mail server. I then went to a couple of workstations in the building and did a Lookup on server.mycompany.com and mailman.mycompany.com, both of which returned an IP of 192.168.1.1. I did a lookup on the IP and it resolved back into server.mycompany.com.
Figuring I'd accomplished enough for the first half of the day, I went to lunch. When I got back, I was bombarded with complaints that mails were being bounced when sent from inside the building, and a few people had received phone calls that mails sent to them had been bounced back to their senders. The error given is:
554 554 <[email protected]>: Relay access denied (state 14).
(This came from Google. The wording varies from person to person but it's always SMTP 554, relay access denied.)
In a panic, I un-did everything I'd done this morning, turning off DNS server, telling DHCP server to begin distributing our ISP's DNS IPs again, but I'm still having the same problem. I didn't see how this could be the cause, but did it just as a precaution.
I doubt I've provided enough information, but does anyone have any initial guesses as to what's going on here?
ARM

Answer 1

Thanks for the quick, easy fix. I'm curious if you know what I might have done to cause this to happen. I don't recall changing any Mail settings.
Sometimes Server Admin "forgets" settings.
Also, apparently something I did wiped out our IMAP mail store. I had a backup thankfully but wondering how I might have done that?!
Wiped out at the file level as in no contents in /var/spool/imap/user?