Ok, thanks a lot for your answer!
My initial plan was to run the mailserver at home on my own box but since I have dynamic IP that's not going to work. I will have to rent a VPS initially to set up the mailserver until I can sort out a static ip from my ISP.
When I setup the debian server, does iRedMail scripts work with systemd?
I see in this forum that the help the members recieve is excellent. I am very impressed!