Simple Postfix help

Hello all,

I'm a new Linode user, but I've been using Linux on a small file server and on the desktop for a few years now. I'm no stranger to bash ;) So far I've managed to build my own Arch Linux distribution and upload it to my Linode and it all works 100% correctly.

However I've got a small problem… I've never set up a mail server before.

Everything else I want to run on my Linode I can do (http, mysql, ventrilo, etc), but Postfix is just a bit overwhelming and despite much reading I'm asking for help ;)

Does anyone know of a simple / straightforward tutorial / howto to achieve the following:

A simple postfix install for two domains. domain1 has only a single user, domain2 has 4. I'd prefer not to have system accounts for each mail user and I'd rather not use mysql to store the mail / users (I know postfix can do this, but I don't know how :P). Postfix must also reject mail for users who don't exist (no catch-all addresses).

STMP auth is important, so only authorised users can send mail through the server.

Once I get the initial setup working and backed up I'll then look at adding ClamAV and spam filtering, but I want to start simple and understand how it works before complicating things :P

Many thanks all, I appreciate you taking the time to read this.

4 Replies

http://www.linode.com/wiki/index.php/Us … ail_Server">http://www.linode.com/wiki/index.php/User:Kangaby#SetupPostfixMail_Server

This doesn't address your question about setting up the two domains and the accounts, but should be useful when dealing with security/spam.

Configuring Postfix with basic sanity checks is covered here. You can read a nice background presentation here on why setting these up is crucial.

Greylisting massively cuts down on spam. The only real penalty is a brief delay in mail delivery. Do both of these first. If spam volumes are still unacceptable, then consider options like DNS block lists (Spamhaus's PBL is reasonably conservative, Zen somewhat less so) or content scanners (e.g., SpamAssassin and ClamAV, either will eat memory and CPU).

I'm not a big believer in HOWTOs, because if all you do is blindly follow the instructions you are left with something you don't understand and can't maintain or customize. So if you are willing to learn a little more, here are some pointers.

@Nexx:

I'd prefer not to have system accounts for each mail user and I'd rather not use mysql to store the mail / users (I know postfix can do this, but I don't know how :P). Postfix must also reject mail for users who don't exist (no catch-all addresses).
No system accounts means you want to set up virtual domains only. See the "Postfix virtual MAILBOX example" section here.

Make sure you look at your "mydestination" in main.cf and ensure it isn't overlapping any of your virtual addresses.
> STMP auth is important, so only authorised users can send mail through the server.
You need to add SASL support, which includes installing another package. I personally recommend Dovecot. See here and here. Dovecot will also let you get your mail with POP and/or IMAP if you set it up to match the mail directories that Postfix is saving to.

And I don't recommend allowing SMTP auth without encryption, so after you get things working you should also look into setting up Postfix server-side TLS.

Many thanks to everyone who has posted help so far, I haven't had the time to read through everything yet but from skim-reading it looks like I should be able to piece it all together ^^

If anyone else has any other input, it'd be greatly appreciated, I'll post back when I have more.

Thanks again ^^

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