postfix makes me wag
I've concluded that my favorite smtp server is postfix. I recently switched from courier-mta to postfix on my main server, and I couldn't be happier with the switch. Courier isn't actually all that bad, but it is definitely... quirky. I remember the first time I set it up it too me over a week to tweak all the 'bofh' options (i'm not making that up) and get mail flowing properly in and out. Postfix, on the other hand, is as easy as pie to configure. I had already been using postfix on my backup mail servers, so creating a config file for my main server took no longer than 15 minutes.
As silly as it might sound, one of the primary reasons that I moved to postfix was courier's developer's refusal to implement an envelope-recipient header. As someone who makes heavy use of aliases, this was a big problem for me. When I received spam or mailing list mail without a To: header, I had absolutely no way of telling to which of my aliases the mail was sent. If I remember correctly, Sam's (courier developer Sam Varshavchik) response to an old mailing list complaint about this was to make the aliases into full accounts where the header could be inserted by a custom mailfilter and then the mail forwarded on to the destination account. Considering I have around 100 aliases, this was out of the question. Instead I switched to postfix, where I now have my envelope-recipient headers, even for alias-addressed mail, without extra effort. I will say that I am still using courier-imap and pop3 servers, and the mta server won't be completely retired until next year. Courier definitely still has it's uses.
Anyway, I am not the only one who thinks postfix is great. There are of course a ton of domains using postfix on *nix for their email infrastructure, but I recently realized that even those using crap like MS Exchange for their email sometimes insulate it from the rest of the world by using postfix as an intermediary. That speaks volumes to me. They can't live without exchange's calendar sharing, etc; but they don't trust it to be public facing, or perhaps found it wasn't up to the task. One organization whom I noticed was doing this is Siemens (which is, according to wikipedia, the world's largest electronics company).
