Mail System Redesign

[Jay Chandler]

Howdy.

I'm at a bit of a crossroads at this point in time-- I've crossposted 
this message to a few places where those far more knowledgeable than I 
are wont to hide.

I've been tasked with rearchitecting the mailsystem for our university.  
I did this once before; probably 9 months ago, since what passed before 
was truly no longer working.

What we have right now is FreeBSD MX boxes running Postfix for an MTA 
that are screening email for RFC compliance, and against several DNSBLs 
(as well as "does this user exist in our LDAP directory?") -- anything 
that fails is rejected, anything that passes continues on.  After that, 
we're running MailScanner on the messages, and tagging according to 
SpamAssassin (configured with sitewide rules because that's how 
MailScanner does things).  From there, we deliver to the user's mbox 
(mounted over NFS, but I've managed to work out the locking issues).  
Dovecot serves the mbox to our Squirrelmail server, as well as to POP or 
IMAP users directly at their client of choice.

I have a few problems with this setup.  The first is user 
dissatisfaction.  They want the ability to white and black list 
individual senders (and possibly domains), preferably as close to the 
beginning of the process as possible.  Obviously I don't want one user's 
whitelisting of spammers.com to affect anyone but that particular user.  
As of now we have no individual white or black listing.

The second is management-- I'm looking to convert to MailDir (to 
obliterate the last vestiges of the locking issues) and institute quotas. 

The third is upper management suggesting that we might look to move to 
an Exchange server for handling user accounts at some point in the 
future, and as much of the white and blacklisting functionality should 
continue to exist if users edit their .forward files to show a 
completely different system (such as Exchange.  Ugh).

Does anyone have any wisdom on this situation that they'd care to express?

-- 
Jay Chandler / KB1JWQ
Network Administrator / Systems Exorcist
Chapman University, Orange CA