Cool. I'm looking to setup a simple mail server at work. It's only purpose would be for users to receive emails about their batch jobs. Would this be an overkill? How secure is this to be exposed to the public IP?
Hi, it might be an overkill. However, you can turn of spam checking, virus scanning and dkim signing in the options and get something that might be suited for your usecase.
How secure it is - well it is used by people in production, and uses standard best practices (firewall, postfix config, dovecot config) to make reasonably secure. Of course we depend on Nixos quickly pulling bug fixes for security issues.
If you give it a spin and run into any problems, please don't hesitate to open an issue on github.