Can't have two computers in houshold join same server

[Knight]

When one person is playing in-game, it works great. When my brother joins ANY server from the server list, I get a "No Message Received" and I am forced to quit. He receives "connecting failed" messages until I am ejected from the game I am in. After I leave the server, he is allowed to join whatever server he wants. What can we do specifically to remedy this issue? If it has something to do with port forwarding etc, I could use a little more in-depth explanation as I don't understand it very well.

Yes I have don't all the no-brainer things like re-installing and things like that. I think it has something to do with the router at my house. It's as if (in my limmited knowledge) the router is saying
"Oh ok you want to play arma 3? Sweet let's do it. Oh you want two computers to play arma 3? Well... since i'm a worthless router and I can't discern between the information of both computers, I'm going to have to kick you both. Sorry"

I also have tried blocking ports 2302 through 2305 on one computer and blocking ports 2303 through 2309 on the other.

I can't find any internet information that has worked yet.

[White8shadow]

COPY&PASTE =https://forums.bistudio.com/topic/119248-two-computers-cannot-connect-to-one-server/

It's an issue with NAT translation. Basically, you've got 2 Arma clients on the same networking routing through the same public IP address. So even though they have 2 separate private IP's, 192.168.0.2 and 192.168.0.3, they're both using 2302, 2304, 2305 as the standard ports...even as outgoing. Most normal programs will generate a dynamic source port, Arma doesn't appear to do that. So when NAT tries to translate your outgoing connections, you're NAT firewall (192.168.0.1 and some public IP) can only support 1 or the other because (to overly simplify things), when you initiate an outgoing connection through a NAT router, it does this:

Private IP - 192.168.0.2
Private Port - 2502
Protocol: UDP
Public IP - 1.1.1.1 (or whatever public ip you're assigned)
Public Port - 2502
Protocol: UDP

And then it forwards your packet to the server. When the server replies, it'll reply to 1.1.1.1 on UDP port 2502. So if you have 2 computers that are trying to use that same IP and Port through the same NAT firewall, the packets will either get routed to one computer or the other computer...possibly both depending on your firewall. Depending on your NAT configuration and/or what router you're using, it could be more or less restrictive.

To get around this, modify your ArmA2 shortcuts and add " -port=2350" to one of the computers. The number doesn't really matter, just as long as it's different from the other computers which will use 2302, 2304, 2305 by default. This will change the client port (though it's not documented) and allow you to connect to Internet servers. Well, at least it should ;-)

Also, another strange thing is that it won't actually use the port you specify, in this case 2350, it'll use +2, +3 of that. So you could technically specify -port=2304 and it'll end up using 2306, 2307. If you specify -port=2303, it'll conflict on port 2305 so don't do that. Skip at least 3 for every computer.

You can always check open ports by opening up a command prompt, typing "netstat -an" and hitting enter. It'll list all of the open TCP and UDP ports. This being ArmA, you're interested in UDP. Dont pay attention to the endpoint column though...it's UDP which is "connection-less" so there isn't any maintained connection. The packets just kind of get there...or they don't and ArmA compensates (or tries to) appropriately.

Let me know if this worked for you.

[Chainsaw Squirrel]

my son and I play dayz, and arma 3 same servers never have had an issue

[KillianM]

My brother and I have had disconnection issues all the time with Arma 3 on the same server, will try this solution

[DEREK]

My partner's friends partner's partner is having a similar issue. I am subbing this thread so that my partner can tell their friends partner a possible solution. I hope I can help my partner's friend's partner's partner with a solution so that their partner can play.

[Mike]

This thread was quite old before the recent post, so we're locking it to prevent confusion.