There are network subnets that have been taken over by Spammers and run by bots.  These networks are recorded and documented by Spamhaus and provide you a quick way to modify your firewall to eliminate these know blocks of Spam.  You will need to have an iptables firewall and add this section to the firewall which will use the ...

When you set up Postfix it is a critical service for your organization.  It is important that you set up a way to verify that the mail server is up and running.  Nagios 3 provides an easy set up to allow you to monitor your mail server.  This tutorial  will help you understand how to add mail service checks for your Postfix Mail ...

I recently checked mail stats on a server and discovered that 71% of the mail that the server handled was rejected. That means the server lost 71% of it's total resources to connections that were either malicious in nature or intended to solicit resources from individuals.  As a result I have gone into a campaign to begin dropping all subnets that I really do not need to allow connections from. Selecting Countries to Drop The criteria that I ...

Using Pre-Built Templates Add the pre-built templates for Postfix. sudo apt-get install apparmor-profiles This will load many pre-built templates that you can use. cd /usr/share/doc/apparmor-profiles/extras Now copy all of the Postfix related profiles into /etc/apparmor.d/. sudo cp usr.sbin.post* /etc/apparmor.d/ sudo cp ...

If you are using Postfix on a server that supports AppArmor like Suse, Debian, Ubuntu, etc., you can use AppArmor to protect Postfix.   AppArmor attempts to protect processes on the server or desktop from security threats.  AppArmor enforces limits on what processes can access on the system.  It attempts to restrict processes to ...