Friends cannot connect to my server.

I have opened all required ports, and my server randomly will let people join. Sometimes it works, sometimes it doesnt, people just get stuck at the "black screen - connecting".



I noticed the ingame warning for kf server says that port 20560 needs both udp and tcp, but the Sticky thread for ports says only UDP. I have only done UDP. Which is the right answer?



I have done the serverbehindnat fix, and I have deleted my system file to let steam redownload it. Nothing has worked consistently.



Thanks.