I've run simple SMTP from a container and not had any issues. I've not tried a more complex stack (but I have thought about it... ) and I was looking at this project
https://github.com/tomav/docker-mailserver
I'm afraid I can't account for it - having never tried it, but it looks like the sort of thing you might be interested in!
PS If you are a newbie, do try something simple first - it took a while to get my head around the differences in the docker tooling (for example this project uses docker-compose which is another tool on top of the docker cl tool).
EDIT: Ooh - a tutorial