I saw some weirdo selling this, so I decided to make my own and release it to the community.
This resource has a config file where you can set the password, error message, etc.
Players joining the server has to put the correct password in order to play on the server.
this is very very nice. knew this was a thing because i saw someone selling it a while back but i never knew how simple it was! only 50 lines and the resmon is 0.00 this is amazing for a dev server or a server that u only want friends to play ect. amazing brother <3