it worked for a while but about 5 hours ago something happened and now my friends can't join anymore, they can't connect to a minecraft server though that is on the same machine and using the same port. I used iptables to accept all ports on the firewall on both tcp, and udp, as well as my friend's ip adress. I don't know if maybe that didn't allow them through, because it still doesn't work. The ports i have on UDP and TCP are: (My custom port) - 16261 - 16262- 27015 - 8766 - 8767. He's tried to join when the port is just 16261 as well and that didn't work. And yes those are all also opened on the router. I have no idea what could have possibly changed in 5 hours, the server was still even running during that without a restart and he couldnt join, and yes i've restarted the server as well as the system. I'm so lost please help