Port 3659 Error

An annoying error since February:

"Game disconnected: Client closed down connection. Check your network connection and make sure that port 3659 (UDP) is open."

According to the Battlefield 4 Forums this error occurs randomly, but mostly if two players behind the same router are trying to join the same server.

The following solution finally solved the problem:

1. Download the "Smart Port Forwarding" Tool (or a similar Port Forwarding Tool):

http://www.softpedia.com/get/Network-Tools/Misc-Networking-Tools/Smart-Port-Forwarding.shtml

2. Install and start the program

3. Right-Cick inside the window and pick "Add new Forwarding Port"

4. Add two forwarded ports like shown on the screenshots below:

Please leave a comment if this worked for you ;-)