Server

The Haraka mail server is able to used common plugins like Spamassassin to enhance the features that it provides.  Using Spamassassin with Haraka is easy to do and reduces the normal resources used by a mail server.

The firewall configuration on CentOS 6 has changed.  This article shows how to add your own firewall rules to the configuration.  CentOS 6 has more options with the firewall than previous versions.

Setting up the Haraka mail server to accept mail into a queue. This is the second in a series on how to configure and use this unique mail server.

The primary reason for adding these repositories is that neither the CentOS repository nor the rpmforge repository contain the same packages that were available in CentOS 5.x. There is some serious lag time which will cripple your ability to move to CentOS 6.

Many Linux mail servers use clamav to scan for viruses. This application is dependable and has a history of updating virus rules quickly as new viruses are discovered.

etckeeper is a set of tools that allows you to maintain the /etc directory in a git, mercurial,darcs or bzr repository. This allows an administrator to commit changes once they have been reviewed.

Haraka, a lightweight SMTP server focused on performance, simplicity and modularity. The Haraka mail server uses plugins built from Javascript to facilitate speed and modularity. The concept of plugins (modules) allows an administrator to implement only those plugins which are needed.

The "check_mysql_count.pl" plugin can be used to count lines in a MySQL database.  It can be used to count either the total number of lines, or the number of lines that meet a certain criterion.

DKIM is more advanced and uses a public key to sign email so that the recipient can verify the sender. The recipient must be able to access the public key using DNS. Yahoo and Gmail both use this technology. This is an example on connecting Postfix to dkimproxy.out for signing outbound messages.