Hello, I don't know if this is the right section but I'm going to ask here.
I'm running a Minecraft Server on a second PC, where I can play with my Twitch followers. The server is running in offline mode, so as I understood it doesn't even check for the auth key of the player. This is because some of my followers don't have Minecraft premium. The problem is: I have been DDoSsed recently, so I bought a domain and used TCP Shield to protect myself from DDoS, but this doesn't protect me from someone using a cracked Minecraft launcher.
Someone recently used my name to log in using a cracked Minecraft launcher and then he joined my server. I got obviously disconnected, and he managed to join successfully. I fortunately was able to turn off the server instantly.
So... I know that putting the server in offline mode makes things worse, but... is there another way to authenticate players, besides putting online mode to true? Like a plugin or something to allow a connection from only one IP?