SkyOn is a free multiplayer modification of Skyrim, based on ScriptDragon and written on C++ with Boost libraries. Alternatively to Siegfree Skyrim Multiplayer.
SkyOn uses TCP/IP protocol using boost.asio to communicate and architecture "client-server". Server allows up to 1000 players, but it will be very slow. By default it allows 32 players maximum.
All settings are in the "SkyOn.ini" file, and they are intuitively understandable:
Both server and client uses one settings file.
You can find an old repository of the SkyOn on the GitHub
Pure server view:
Screenshot of implementing one of SKSE functions with ScriptDragon:
Here`s a video demonstration of SkyOn testing.