small mail server

[Greg Groth]

Robin Becker wrote:
> I'm looking for some advice on using one of our existing freebsd 6.x 
> servers as
> a mail server for a small number (<20) of users.
> 
> Our existing provider gives us
> 
> 1) pop3/IMAP for reading mail
> 2) SMTP for sending, but we need to read mail before using smtp; I guess 
> this implies we don't need to authenticate directly.
> 3) web based interface for adding users and redirections etc etc
> 4) spam filtering (presumably based on their large user mail volume).
> 5) white/grey listing
>

1. If your users save a lot of mail on the server, check out Dovecot (or 
any of the IMAP servers that use Maildir).  I started with IMAP-UW, but 
the response time on web frontends for users with large Inboxes was 
dismal.  IMAP-UW is simple as an anvil as far as getting it up and 
running, Dovecot requires a tad more work.  While setting up either one 
of these is trivial, converting existing formats to another (Mbox to 
Maildir) is not, choose wisely now, and save yourself a headache down 
the road.

2. Pick your poison.  I've been using Sendmail for years and find it 
simple for small installations such as mine, and found Postfix confusing 
simply because of my familiarity with Sendmail, YMMV.

3.
a. IMHO, simplest web front end for email - Squirrelmail
b. My personal favorite web front end for email - Horde
c. Web front end to add users, only Webmin comes to mind.  (Webmin is 
for server administration only.  There is a companion for users called 
Usermin that has an email frontend, but I didn't care for it all that 
much - YMMV)

4&5. spamassasin.  White listing is a breeze.  I never tried 
grey-listing, although it's my understanding that spamassasin can do 
this as well.

A couple of other things that you may not have thought about regarding 
off-site access.  Currently we need to allow our users to be able to 
send remotely.  In order to do this, we needed to do two additional 
things, set up SASL for SMTP authentication was the first - so we didn't 
have an open relay.  Second - we ran into an issue with the ISPs of 
certain users blocking the SMTP port.  We installed stunnel for SMTPS, 
which isn't currently being blocked, and no issues so far.

Another thought is to investigate any software you plan on installing 
with the email client your users have on their desktops.  I currently 
have everyone using Thunderbird, which plays nice with everything I've 
installed on the server.  Clients such as Outlook can have issues with 
certain software, and workarounds have to be implemented.  Once you 
choose an MTA or IMAP server, google around and make sure you know what 
you're getting into in regards to your mail client.

Best regards,
Greg Groth