Mail Delivery / Amavis / Spamassassin etc

[Steven Heimann]

On Friday I took the leap and replaced our firewall at work based on
RedHat 9.0? with Ubuntu 5.10.  It went surprisingly smoothly.

I seem to have postfix on the firewall working as a relay to our
internal mail server (Lotus Domino) and Amavis-new working with Clamav
and Spamassassin.  Over the next few months I plan to migrate all the
mail off the Domino server and onto Linux . (Domino is actually running
on Linux but it is still proprietary and getting in the way of plans for
improvement)

In the past, although I have run Spamassassin on the firewall its
effectiveness has been limited.  I think this was because I didn't have
the ability to integrate any sort of Bayesian analysis into the system
because I couldn't get Spamassassin access to the Domino store.  I
simply took the delete any mail with a score over 7 strategy and used
rules du jour occasionally.

On the new mail server this shouldn't be a problem.  I will transfer the
spamassassin functionality from the firewall to the mail server so I can
have users file the spam into local folders and run the Bayesian
analysis.  At the moment I have Spamassassin tagging the subjects of the
email.  I think this is a bad idea because that will affect the
Spamassassin analysis.

I have a number of questions.

I haven't yet worked out how to integrate this analysis into the server.
It appears Evolution is set up with this integrated.  Is it better to
let Evolution handle it?  However, because I still have some Lotus
clients I think I want to try to integrate this into the mail server.

I can't seem to find how the Ubuntu mail is delivered from postfix to
the user.  Is procmail used?  How would I arrange for identified spam to
be delivered to a separate folder in each users mail store?

I have been using offlineimap as a method of reading emails from the
Domino server to my own computer for a couple of weeks and it is quick
and reasonably reliable.  I plan to use it to transfer each users mail
from the old to the new system progressively.  Should I try to set up
each users mail using maildir or keep the mail inside Evolution's own
store?

My users need to have remote access to their mail.  I am inclined to
keep their mail stores outside Evolutions native store and use
offlineimap to sync mail to their laptops.  Which imap server would
people recommend?  There seems to be too many choices.

I am sorry this is a bit long and rambling but I couldn't see how to
make it more concise.

Thank you
Steven