Good option appliance Linux Distro
If you *really* want to run your own on-premise "appliance" version of (Linux for example) to make this sort of thing "less fuss, less muss" and still retain control (ie, physical access,ownership) of your box, maybe take a look at "ClearOS" Community edition:
https://www.clearos.com/clearfoundation/software/clearos-6-community
ClearOS is based on what used to be called SME server / E_Smith server. ie, it has been around for a while; it has a good history of "stable, well maintained, works, and not bleeding edge".
I use ClearOS as a variety of SMB sites and it is super solid. Pretty much all the admin stuff can be done from the web-admin GUI. CLI via SSH is there and available if-when you need/prefer it.
It is free (community version) but you do need to register (free) with them. If you don't like that you may need to look elsewhere. But in terms of a very well built, well thought out, mature "appliance" distro - you can add roles:features as needed (Mail, anti-spam, anti-virus, greylisting, SMB:Domain controller, etc etc etc) - boat loads of options.
Highly recommended.
Tim