I am using MultiMC 5 to host my minecraft instances. So I can see status updates on the console. Whenever my friend tries to join one specific world, I begin to lag like hell and 30 seconds later my friend gets connection timeout. The console then says:
After processing 2500 packages there is still 10.000.000 packages left.
And then slowly counts down, but then times out.
What is causing this timeout?