Take a look at https://hacktechonline.com if you are into hacker sims.
HackTech is a semi-realistic hacking simulation game. It's primary goal is to make a "virtual internet" where the player can mess around with some servers ^.^ and complete missions.
This game isn't made to learn people how to crack servers or how to use exploits. The reason I wrote this game is to make the player have some fun.
Take a look at your ingame bookmarks, there is a very usefull link from the start.
Enjoy the game! ^_^