For all those who are new to this topic, a Runescape Private Server is a server that is not owned by Jagex, but by someone else; and that can be completely modified by the owner.

For you to understand better what a private server is, think of Runescape "Worlds". A private server is like a separate "World", that you cannot enter with your normal Runescape account, and is completely different from the Official game.

Are these servers legal?

Actually, they are not. All private servers, are illegal, and it depends on the official creator to take the actions to stop servers.

To make a private server, hackers had to first hack the official files and get the source, then from that they can make private servers.

How to play a Runescape Private server

Here is a list of many runescape private servers. The instructions on how to connect are in their own webpage.

How to make your own Private Server

It is quite easy! Check this article to learn how to make your own private server.