Setting up an email server is one of the hardest things to do properly that I have come across in all my time working with PC’s. There are many methods to achieve this goal but hardly any of them that are secure and free / open source are particularly easy to set up, configure and maintain.
Welcome to iRedMail the Free, Open Source Email Server Solution.
They have complete install guides that are simple and quick to follow, as their site suggests it is beneficial to follow the guides for Ubuntu, Suse, Debian, CentOS etc on a fresh install. Make sure your new install is connected to the web and that you are able to open the necessary ports on your router.
I can personally recommend installing on CentOS and in no time at all you will have a fully working email server with webmail and antivirus too!
You can always install CentOS in virtual machine on your current OS if you are already running MySQl, Apache, PHP etc
Their guides are so precise and well written it is pointless me trying to do any better: http://www.iredmail.org
