The following are a serie on "Virtual Users And Domains With Postfix, Courier And MySQL (CentOS 5.1)" in howtoforge:

There are a number of tools out there that helps you to test if a domain has been blacklisted. There is a good one:

http://www.blacklistalert.org/

 Reference http://www.imminentweb.com/technologies/implement-domainkeys-identified-...

• an email
• http://www.ijs.si/software/amavisd/amavisd-new-docs.html#dkim

Install and configure DCC

The current stable version for DCC in Portage is 1.3.55. That's a bit too old. You can check so by doing "emerge -pv dcc".

To get the latst DCC software, goto http://www.rhyolite.com/dcc/, and then read http://www.rhyolite.com/dcc/INSTALL.html.

Now follow My other article Setup DCC to Use Remote Public Servers.

authdaemond

You can change the number of authdaemond processes in the file /etc/courier/authlib/authdaemonrc:

daemons=2

This line sets the number of authdaemond processes to 2.

saslauthd

To change the number of saslauthd processes, edit the file /etc/conf.d/saslauthd (in Gentoo):

Install Spamassassin, ClamAV, and Amavisd-new

You can just run emerge on these packages. Note that as of today, the mail-filter/spamassassin in Portage is still version 3.2.1, which is a bit old. If you want the latest, you can find the latest dev version from Gentoo mail-filter category packages page. To install the masked mail-filter/spamassassin-3.2.5, put the following line in /etc/portage/package.keywords:

Sendmail libmilter

This is the prerequisite for the DKIM package. Install Sendmail libmilter with poll option:

Add the line below into /etc/portage/package.use

mail-filter/libmilter poll

Now emerge the package

# emerge -v mail-filter/libmilter

Install SPF policy server

Check openspf.org for the latest development. For Postfix, http://www.openspf.org/Software currently lists two packages: python-postfix-policyd-spf and  postfix-policyd-spf-perl. It says that python-postfix-policyd-spf is more feature.

Install python-postfix-policyd-spf:

Download the package, extract the tar ball, and follow the README in the source tree.

USE flags:

In /etc/make.conf, add the following to USE

imap libwww maildir sasl ssl

In /etc/portage/package.use, add the following lines:

Download and Install Pyzor

First, read the page Using Pyzor in SpamAssassin.

Then, download Pyzor from sourgeforge.net. Unarchive the tar ball, and follow the instructions in INSTALL file inside the source tree.

There is a usage file in the source tree. Or you can read it from online.