[sclug] Recommendations for mail server

[Keith Edmunds]

On Thu, 13 Jan 2005 20:52:02 +0000
Drew McLellan <lists at allinthehead.com> wrote:

> Hi everyone - I've been lurking on this list for a couple of months, so 
> time to introduce myself and ask some advice too.

Hi Drew, welcome.

> I've got a box running Debian Sarge as a dedicated web server off in a 
> datacentre somewhere. The box currently has exim installed. I need to 
> configure a basic mail setup so a small handful of people can use POP3.

Exim is the Debian standard, and a reasonable SMTP server. Personally I use
Postfix on the servers I configure, but that's mostly down to personal
preference.

> Requirements:
> 
> a) POP3 boxes
> b) SMTP relay w/ authorisation

They're separate things. POP3 will be provided by a POP3 daemon, of which
more in a minute, but the daemon simply serves up mail which has already
been delivered. SMTP relaying is a function of the MTA, and Exim or Postfix
will each do that. My personal preference is for Postfix with SASL
authentication, which can easily be tied in to PAM authentication - in
other words, you can create a normal user account on the server for a user,
and they can use that username/password to authenticate with Postfix to
send mail

> and ideally:
> 
> c) web interface for account maintenance (webmin's ok)
> d) work with a standard webmail tool like squirrelmail.

If you need a web interface then I'd recommend webmin. Squirrelmail - an
excellent application - reads from an IMAP server, so your earlier
requirement of POP3 is in conflict here, probably. If possible, I'd
recommend IMAP because all mail is then kept on the server, meaning that
there is only one location to backup. It IS possible to access mailboxes
by both POP3 and IMAP, but you should be SURE you want to do that before
going ahead.

The IMAP server I'd recommend is Dovecot; it also includes a POP3 daemon.
 
> I guess the main problem I have is understanding which tool does what. I 
> guess an MTA like exim will route mail in and out of the box, but does 
> that leave me needing something else to handle the accounts? Or do I 
> create system accounts? What about POP3? and all those sorts of dumb 
> questions.

You can have a "virtual" mail server that doesn't need a system account for
each mailbox, but unless you have a huge number of mailboxes this is
probably overkill. Roles: the MTA does indeed route mail in and out of the
box as you say. Incoming mail is passed to a Mail Delivery Agent (MDA),
which may be part of the MTA or separate from it. The MDA delivers the mail
in a given format, typically mbox or Maildir, to each user. A POP3 server
will read each user's mail and deliver it to their local mailbox, typically
part of their Mail User Agent (MUA), such as Outlook/Thunderbird/etc.
Usually POP3 then deletes the mail from the server. An IMAP server also
serves up mail to the MUA, but this time the mail remains on the server.

Does that help at all? Or has it spawned 254 new questions?

Keith

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