I’ve been running my own mail server ever since I read NSA-proof your e-mail in 2 hours. In reality it took a week to get something working using this guide and another week to get it to a reasonable state. This ordeal inspired me to dockerize my mail server and make it possible for anyone to actually set up a mail server in 2 hours. It has only 4 configs and if you are already familiar with docker and git most of the work is around setting up DNS. The instructions are in the repo. Let me know in the comments or on twitter how long it actually took.