So, JK2 1.02 has a new master troll who's not getting tired of attacking JK2. What is new about it is that the troll is now also attacking players and not only servers.
JK2 is a very old game and over the years people discovered a shitton of security holes / hacks / ways to crash servers etc.
Currently the "hacker" is using a security hole which makes it possible to redirect clients to his own server no matter onto which server you actually wanted to connect to. On his server he could
then use other security holes to execute e.g. a virus on your PC.
However, most likely hes just a troll trying to force you to play on his server.
How can I protect myself from all this stuff?
JK2MV. It has fixes for 21(!)
Current JK2MV versions don't contain all of the fixes though. We will try to release a new version in a few days.