Scope And Requirements

These pages tell you how to configure the Postfix mail-server, the Fetchmail mail-retrieval utility and the Procmail mail filter. Target platforms are single-user, dial-up workstations, ML security level 3 (machines with a lower level shouldn't be connected to the Internet anyway, whereas higher security level machines usually are servers which use Sendmail instead of Postfix).

I assume dial-up to be configured properly already. It doesn't matter whether your machine is connected to a local network or not. An outward address to send test messages to might be handy. Since your machine isn't connected to the Internet 24/7, you will need a POP/SMTP mail account on a server (Usually ISPs bundle one POP/SMTP address with a dial-up account) to collect your in-mail.

These software packages should be installed:
- postfix
- procmail
- fetchmail
- fetchmail-conf
- a mail reader

I would also suggest to make a backup of your mail directory before you start. None of the steps described here should pose a threat to mail already stored on your system, but better be safe than sorry ;-).

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Why A Dedicated Mail-System?

If you are perfectly happy with your all-in-one monster mail application, you can skip these pages.
Read on if you

• find that your preferred mail reader doesn't include POP/SMTP support, advanced filtering etc.
• want to automate your mail system as far as possible,
• get lots of mail (> 200 mails / day),
• make use of cron jobs a lot,
• want to make use of the possibilities internal mail delivery offers,
• are curious what you can do with your mail on a Unix system,
• are someone who just loves to fiddle with knobs and options. :-)

Of course you will have to configure some stuff first, test and then test again, have a look at log files etc. But once you've got it up and running, you will wonder how you have got along without it so far.

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Mail Programs

There are more than 20 different programs for GNU/Linux for reading and writing mail. Once you've finished configuring your mail system, you won't need any of them, since you will be able to do that on the command line *grin*. Seriously, finding a mail agent which suits your needs can be a daunting task.

If you are not content with the programs your ML CD offers you (Netscape / Mozilla Messenger, KMail, Balsa, Pine, mutt, elm and exmh/nmh), you should really spend some time to find one. A few programs you might want to have a look at ( more at Freshmeat):

• Arrow from NewPlanetSoftware. Arrow features a nice and clean interface and doesn't require any of the big widget libraries. While not being suitable as a standalone mail program (no filtering, no multiple POPs etc), it will fit in nicely in a Unix mail environment.
• Mahogany is a cross-platform mail agent. While being quite a huge download (three MB), it offers tons of features (e.g. dial-up networking management, SSL support, configuration wizards).
• Aethera is a Personal Information Manager (PIM) with email capabilities. It is primarily aimed at KDE users.
• Evolutionby Ximian (former HelixCode) will be a part of their GNOME desktop to be released later this year. Dubbed as an 'email environment' it will also include a calendar and a contact manager.
• Other interesting programs include Sylpheed, CSCmail and Pronto!.

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Technical Terms

As it is with technology, you have to learn some new terms and abbreviations, since you will encounter them in documentation:

• DNS is the Domain Name System. On a network, each machine has a number and a name. Networking programs use numbers to identify another machine, whereas humans prefer names. DNS maps the name you use to its according number which in turn is used by the networking layer to identify and connect to other machines.

• FQDNstands for Fully Qualified Domain Name. This includes the name of the machine and the domain it belongs to. If your machine doesn't belong to a network, its machine name is by default "localhost" and its domain is "localdomain" making the FQDN "localhost.localdomain".

• MTA is short for Mail Transport Agent. Roughly speaking this is the application which sends your mail to the outside world (or to different parts of the network or even the system itself).

• MUA is short for Mail User Agent. The application which you use to read and write your mail.

• Smart- or Relayhost is the mail server which your MTA sends all outgoing mail to for further relaying (presumably that's your ISPs server). It's up to you to use a Smarthost or to deliver the mail directly from your box, I will describe both ways.

• Spamis common Internet jargon for irrelevant or inappropriate messages / mails / postings usually of a commercial nature. The proper name is Unsolicited Commercial E-mail (UCE).

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Next: Configuring Postfix