Building Postfix from source can be a rewarding experience with great results.  This tutorial will show you how to do a basic build and then following tutorials will show you how to build in additional features. Download Source Code From Here: http://www.postfix.org/download.html When you download the source and unpack it you ...

Mail Does Not Send A common problem is finding that mail is not sending correctly and that the /var/spool/clientqueue is filling up with files. This directory can actually shut down your server if you do not have a separate directory for /var when this happen. The speed at which this happens is determined by the amount of mail that is being sent. Cause of the Problem: The cause of the problem is most often a mis configured firewall or a mis configured ...

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 ...

Listed here are a number of header checks that do work but they are ineffective for the most part.  Here is the problem.  When you look at these examples they have a Subject that you are searching for.  As a result you will be writing header checks until the day you die, not good.    My thinking is that you will want to discard ...

This tutorial will show you how to set up your log statistics to be mailed to you every night so you know what is happening with your Postfix Mail Server. Set up a cron job so that it will run at 11:55 PM, just before midnight as you want to get all of the logs for that day.  Be sure to give enough time for the script to run before the next day.  Here is the line to use if you have install pflogsumm at /usr/pflogsumm, see this article for ...

One way to implement content filtering is to use regular expressions in your header, mime_header, nested_header and  body checks.  This should be simple matches to regular expressions.  The goal with this example is to eliminate non-English characters, since we cannot read them anyway.  This will drop all non-English ...

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 ...

Create Users Create the users on the system. Create users with the false option so they cannot log into the server. This is an added security feature. A. Create the User useradd sue -s /bin/false passwd sue A common mistake is to forget to provide passwords for these users. B. Use saslpasswd2 to create a cyrus account for the ...