I read this article on HowtoForge and decided to give it a try. I was not as successful as the author.
iRedMail: Full-Featured Mail Server With LDAP, Postfix, RoundCube, Dovecot, ClamAV, DKIM, SPF On CentOS 5.x Debian (Lenny) 5.0.1
iRedMail is a shell script that lets you quickly deploy a full-featured mail solution in less than 2 minutes on CentOS 5.x and Debian (Lenny) 5.0.1 (it supports both i386 and x86_64).
My first try was to use the script to update a Centos 5.3 workstation installation. It went smoothly until I tried to update look at the keys used by DKIM. I ran into trouble with the LDAP option. OpenLDAP would not install do to a missing file. So I took the Mysql option. That was when I found a series or problems. Most of the problems were minor. My initial mail userid used Chinese. Since I was particularly interested in DKIM I was disappointed to find out that Amavisd was running at a version that did not support DKIM. I quickly realized that this was taking too much time and a better solution was to install a virtual machine using the iRedOS. This is a Centos 5 installation with all of the prerequisites already installed.
Creating a virtual machine mail server went pretty smoothly. The only problem I found with the installation was that I was unable to send mail. I quickly realized that I needed to install Webmin so I could perform normal system maintenance and troubleshoot. After I installed Webmin I found my problem. Postfix thought Yahoo was an unknown domain. Although I am not familiar with intricacies of Postfix I found that if I removed the configuration parameter â€œreject_unknown_recipient_domainâ€ I could send emails successfully. This is a not a fix but it will work for me until I figure out the problem between the DNS and Postfix.
My next trick is to set up the mail server as a mail relay to my Exchange server. Technically this could be a first step in migrating off of Exchange to a non-Microsoft cloud computing environment. There are a lot of good things to be said about Exchange but there are even more good things to say about cloud-based email. Making the transition to a low cost, highly dependable, feature rich email environment with the least amount of pain is the challenge for both the Microsoft and open source communities.