A little over a week ago I began an upgrade that I have waited over a year to do. It was the summer of 2006 when Apple announced MacOS Leopard Server and I knew that I wanted to move to it.
With a two server internet presence, one of my machines was running QuickDNS Pro (DNS), Eudora Internet Mail Server (SMTP and POP), and LetterRip Pro (mailing lists). My other server was running WebServer 4D (a legacy and aging HTTP app) and Rumpus (FTP).
Leopard Server held the promise of bringing me up to date, and adding services such as IMAP, blogs, wikis, VPN, php, and MySQL. So when it finally shipped in October 2007, my order was in!
The first goal was to replace DNS, mail, and list services. This went fairly well, but the configuration of the SMTP server "went south" and I limped along for nearly six days until the right combination of settings was finally attained.
While Apple is known for their ease-of-use Macintosh interface, Leopard is truly a UNIX solution. Apple has added some GUI's to take away some of the intimidation of UNIX, but the bottom line is that it is still UNIX under the hood. In the case of the mail component, it is actually separate open source projects to handle SMTP, POP, and IMAP. The SMTP is handled by Postfix, and I found myself needing help.
So here's where the credit is due... I found this web site --
http://osx.topicdesk.com/ -- run by Athanasios Alexandrides. I believe he's in Switzerland. He was a huge help and got me back online. So if you find yourself in a similar situation, configuring Leopard Server's mail components, he's my "go to" guy!