Fetchmail, Cyrus and Exim4 – a Mail Server for Linux

This is a short installation HOWTO for a mail server for Linux. I’m on Ubuntu 9.10 (Karmic Koala x86_64). A mail server basically consists – and the most Windows user won’t believe it – of three parts. This is because it gives you the freedom to decide which components you exactly want to use. There are a bunch of different applications out there, and even a higher number of constellations. The components usually a mail server consist of are:


  1. Mail Retrieving Agent (MRA, here fetchmail)
  2. Mail Transfer Agent(MTA, here Cyrus)
  3. Mail Delivery Agent (MDA, here Exim4)

What do they do?
Fetchmail gets your mail from your provider (POP, IMAP). Cyrus is actually your locally installed mail box, against which your mail client (e.g. Thunderbird) connects to, and where your account and mail data are stored. Exim4 sends the mail to a SMTP host, usually also your ISP provider.

Why these guys?
The reason I’m using this combination isn’t very straight forward to explain, but is far from being exotic, but is more due do some historical events in my past. But let me put it like this: Exim4 is default on Debian systems like Ubuntu. Fetchmail is easy to configure and debug and Cyrus is because of its sieve (Spam filter, not part of this HOWTO) capabilities and because it was one of the first sealed IMAP servers – means: for local purposes available only – at all.

Ok, let’s start in the above given order.

Click here, or use page navigation: