So my current project has been to setup a mail server and I think I’ve been largely successful in that goal.
My next step (for those interested) will be to enable true ssl with signed certificates. The other issue I have revolves around fact that my website’s subdomains mail and blog are hosted on a virtual machine, mail.warbel.net, whereas www.warbel.net is hosted on the VM host itself (atlas). The trick will be to enable the webserver on atlas to operate as a reverse proxy that will automatically accept all incoming port 443 and 80 connections then forward them, or accept traffic to the appropriate sub-domain.
There are free signed certificate sites available, namely https://letsencrypt.org/ which I will use to achieve these ends.