But I only set it up once, several years ago now, and I seem to recall that the initial config was a bit fiddly. Qmail does the virtual user account thing as well, I think, but don't know about the rest. Postfix definitely does virtual accounts and is the one I use personally; I'm pretty sure that putting the other stuff on it is possible, but suspect it might be a chore.

I've got all my users and aliases in a MySQL database backend. There are various guides for doing it, the usual problem bit comes with hooking the pop3/imap thingy in though if you pick one that can use pam and sasl authentication it gets a lot easier. There doesn't seem to be a ready made thing around to do it, but there are plenty of guides. I'm using Exim, Cyrus and Squirrelmail with MySQL, I've got a half finished vacation handler that I've not told anyone about and there's currently no way for them to change their passwords as I need to overhaul our entire authorisation system at some point and I'll add that then.

I run exim + Courier IMAP in Maildir delivery mode. Both can use LDAP without effort to handle the accounts. exim is able to handle the auto-response from data in the LDAP directory.

You'll find plenty of documentation with google on exim + LDAP.
Courier POP/IMAP is trivial to setup with LDAP.
Quota support from exim and Courier works well.

Horde / IMP is ok as a webmail, and includes the ability to change password in the LDAP directory.

I use a slightly unusual auto-responder setup (I have start/stop dates along with the text) so I have a simple PHP interface to the responder.

This setup is also very scalable if you serve the Maildirs from a NAS or SAN. You can just drop additional front-ends to increase capacity. There may be out-of the box system that provide all of this (such as Zimbra, with calendaring thrown in), but they rarely scale easily (ie. require direct access to the disk).

And finally, it's quite easy to write PHP (or Perl) front-ends for the LDAP system. Since you never require access to the server disk, it all works beautifully.

You can easily throw in clamAV for anti-virus, spam assasin for a simple anti-spam.

Granted, it's not free, and I doubt it runs on Debian.

What's the account management for all the users, if the mail account is a nullo ? Why aren't mail accounts tied to logins ? Or do the work machines not have any login ?

Heck, there's gmail for business too..

FYI: You might have to apply a patch to Qmail for the .vacation stuff, but all should be fine from there.

If you want to use your existing installation it shouldnt be a problem. Both exim and courier should run off of SQL LDAP or virtual user flat file. I believe both can also do a mixed mode while you transition over, theyll query auth methods in order of preference.

For an MTA qmail is nice once you know it. Personally if youre already on exim I dont see any great reason to change as long as you use maildir+. Both have plenty of chaining options, filter support, and can run over NFS. Courier, like people mentioned, can be a picky bitch some times. We ended up switching to Dovecot and I can wholeheartedly recomend it. Nice plugin type architecture and a sane apache style configuration are the biggest selling points to me. If courier gives you any lip at least give dovecot a try.

For the .vacation and password changes I dont know the exim options. Qmail has a web based account manager called QmailAdmin. You can use that stand alone or it has plugins for Squirrelmail to tie it into the Options area.

If youre not adverse to a major change QmailToaster is a nice setup. The guy who packages it all up also does installs, support, and consulting. If you have any questions about setup/maintenance/performance the qmailtoaster mailing list and forums are great. Its a smaller community so when you ask a question youll get an actual factual answer.


-Lin Dze
Arbeit Macht Frei