[NTLUG:Discuss] RE: Replacing exchange

[Jerry Haltom]

Depends what features you need of Exchange. Here's the pickle:

If you are using Calendaring and Contacts: The only centralized way to
do this is in Outlook. There are not yet any open source clients that
support reading calendaring and contacts from remote mail folders. We
seem to have some moral problem with storing stuff that shouldn't be
stored in a mail server, in a mail server.

However, if you are using Exchange, chances are you are using Outlook,
and probably want to continue using Outlook.

I recently set up a Exchange replacement using Cyrus-IMAP on the server
and Outlook on the client. There is a "fairly cheep" plugin for Outlook
made by Bynari, Inc (located in Dallas, in fact this list is apparently
hosted by them???) It's about 25$. What it does is allow Outlook to save
messages/mail/contacts/calendars/tasks into standard IMAP folders on an
IMAP server.

Requirements on the server end are a IMAP server that supports ACLs.
Cyrus-IMAP is the only open source one available that does this to the
best of my knowledge.

Delivering mail into Cyrus-IMAP is a matter of setting up a proper MTA
(Exim, Postfix, qmail, sendmail, etc). I have done it using Postfix.

Exchange relies on MS Active Directory for user and mail/address
information. Postfix and Cyrus-IMAP will both need to reference the same
location for user information. Cyrus supports quite a few different
methods of user information storage. I implemented Postfix and
Cyrus-IMAP against an OpenLDAP backend.

I also set up Samba against the same LDAP backend.

The end result: A functionally equivelent "Windows Network", implemented
on Unix servers.

PS: Unix clients, such as Evolution, Balsa, Kmail, Pine, mutt, etc, can
of course connect to the IMAP server. From these clients the Calendar
folder will appear to just be filled with a lot of gibberish messages.
Each message is an entry on the calendar. Don't mess with them or you
risk breaking Outlook.

Jerry Haltom
Feedback Plus, Inc.