My experiences and solutions to the co-op joining problem

[Gilex442]

Hi All,

Like many of you, I experience random "Failed to join game" messages when playing co-op with my friends on PC. Sometimes we can play fine, other times it doesn't work at all.

Here are my thoughts on the problem. These could all be very wrong, but I have a strong IT background (BCompSc).

First lets start with what I know;

1) Of all the ports that are posted on here, the one I can confirm 100% the game wants is UDP 3569. When the game starts, requests a upnp binding with the description "EA Tunnel", for this specific port. You must forward this port to your internal address if you are using a NAT. I also mapped UDP 9999 but I cannot confirm this one is needed.

2) An outbound socket is also created using this port for sending traffic (source: firewall logs from my router).

3) My game reports I have "NAT Type: Strict". This doesn't really mean much to me, as I have allowed upnp port forwarding and most NAT implementations are of a hybrid type rather than strictly one way.

Now here is what I think, followed by the steps I have taken to solve the problem for myself;

The game uses VoIP, there are several ways to do this, some of which do not work very well with NAT technologies. When my friend would try and join a game I hosted, I would see his username appear in the game but his connection would eventually fail. I would never hear a voice, which I would when the join actually worked. This is when I decided to experiment with my NAT a little bit to try and force my outbound port translation (PAT) to give me the port that the game had actually requested. It was when I changed my NAT to force static outbound port mapping, that joining games and hosting games started working consistently.

This can mean a few things, the game could not be detecting the type of NAT I have correctly. This seems unlikely as it reported that I did have a NAT. The game could be trying to start a VoIP connection using the SIP protocol, which requires a static (known) outbound port and when it fails, it drops you from the game instead of turning off voice chat. It seems silly to me that if an application correctly maps a port inbound, that a connection into that application would still fail because the source port was randomized.

Please let me know how you go with this, I am interested to find out if it is NAT outbound port mapping.

[akarainer]

Could you explain how do you actually do the things you stated? There is a lot of terms im unfamiliar with.

[confusedduck]

this is quite the thing I suspect I'm experiencing

it seems that crappy netcode is a common thing amongst ea games

I'm on pfsense and I've done everything apart from messing with outbound nat (never done that before didnt want to brake it bar)

I've opened all traffic and redirected it to my machine, even made some floating rules in case the problem was with the packet consistency or wrong state

the weird thing was that EA Tunnel worked sometimes (was up on upnp service) but it was basically at random

and the weirdest thing thou was that it sometimes worked - I could connect to others and other could connect to me with no explanation nor consistency what so ever

I even wondered if the actual host of the game was changed to the person connecting to me.

and for all you one pc people who got it with the pack of chips - turning off nat is not a valid solution we have it for a reason - I wont be dismantling my entire lan because a company is not competent enough to provide a working product to the customer, or at least disclose a most probable issues which I would guess would take a ea coder 5s to come up with

@gilex442

thanks man - seems like a solid invastigation

in regard to failed matchmaking and the guy showing with no speaker icon I thought it was simply a ghost of initial handshake provided via some ea cetralized service well.. lack of debug and proper error messages is tragic

cheers