Ongoing Connection Issue in bf4 Client Closed Down Connection Port 3659 UDP

Did you assign a static IP address to your PC in the router settings?

no

Without a static IP address the router will assign the PC a new IP address and the port forward settings will no longer work.

Hello all

Me and my friend are also affected on and off by this issue. It is going on for years now without us finding a reliable solution: We uninstalled and reinstalled Battlefield4, repaired it, emptied caches, tried some stuff with port forwarding and firewalls(both Windows and on the router), switched even PCs and Windows(from 7 to 10 to 11). Strange is that if the error occures, not all servers are affected.

Just two quick notes here concerning firewall and portforwarding:

1. Assigning a "static" IP address to the device(PC, PS etc.) is only necessary if the IP gets picked by another device in your network, you cannot reserve the IP address in your routers DHCP settings or if the router does not link the port forwarding rule to your game devices MAC address. Unfortunately every firewall/router handles that differently so there is no general advice to give here.
2. This whole opening and forwarding of ports on the firewall/router does not make sense from a networking point of view. Battlefield on your computer always opens up a connection to the server from INSIDE your network(usually on a so called "high port"). This connection stays open as long as you are playing the game. The "return" port may be 3659, but this is already advertised by the connection itself and not statically on the firewall. That's what is called a "stateful" firewall. And that is also the way many devices can play the same game from the same internet connection: Every new connection will advertise another "return" port. Opening a specific port from outside makes only sense if something wants to connect to your network without "being called" from inside first. For example if you run your own game server(or whatever) at home.

My conclusion: This is entirely a bug from EA which needs to be taken care of by them.

thank u for the detailed explanation, it makes a lot of sense. i totally agree with ur conclusion after trying so many fixes on our side, it really seems like this is an EA side issue that we as players can’t fully resolve. Hopefully they will look into it eventually. appreciate u sharing ur experience and the networking insight it helps clarify things.