PC and PS3 can't not play game at same time

[ksmith12305]

Hello,

Me and my roomates downloaded battlefield bad company 2 beta. He has a ps3, I have a PC. We can each play it online as long as the other person is not online. When either of us tries to get online, while the other is playing, the person already on gets booted out of the game. (Connection to server is lost). I can get back online right after and kick him off. We have a belkin router. We are both direct connected, we have tired setting one of outsied the dmz, and we have checked the ip addresses. Any advice? Thanks alot

Kevin

 

[eibgrad]

The problem you’re probably having is this game requires you open and forward specific ports on your router’s firewall. If you haven’t done this manually, your PC or gaming console may have done it automatically using a feature called UPnP (Univeral Plug N Play). When forwarding is established, it can only be done for ONE machine on your network for any given port (or set of ports). And that’s the crux of the problem. You’re both using the same game, therefore require the same ports on the firewall be forwarded to your respective machines, but forwarding is only possible to one machine at a time. If those ports are currently being forwarded to the PC, then as soon the PS3 version is started, it closes those ports, reopens them, and starts forwarding those ports to itself. And round and round you go in a vicious circle.

This is just a fundamental limitation of using a NAT router. The only way to get around this is to either not use NAT (instead, obtain a public IP for each machine), or else reconfigure the game on either the PC or PS3 to use DIFFERENT ports. The problem w/ this second approach is that many games don’t let you change ports. And if it doesn’t, you’re pretty much stuck.

 

[Brian_tii]

x2 with everything eibgrad stated... the only thing you MIGHT be able to try is disabling UPnP on your router (which if you ask me UPnP is a bad idea anyway).... with that disabled you maybe able to force the game's peer to peer networking into a little different mode. With all the connections coming "outbound" the NAT might work ok because the router / firewall will translate the source ports to the correct IP behind the host. In other words... if you lock it down... it MIGHT work better, though you'd never be the p2p "host" and finding games to play online may take longer. Again, I'm not sure, but it's certainly worth a try.

 

[ksmith12305]

Hey Guys, I tried the port forwarding with the router. Me and my roommate both have the pc copy. We put different ports for each of our computers. At first, he kicked me out, but eventually it let both of us play. Today, its back to kicking us out. Thanks for the replies.. I will just keep messing with the router.
Kevin

 

[eibgrad]

Hey Guys, I tried the port forwarding with the router. Me and my roommate both have the pc copy. We put different ports for each of our computers. At first, he kicked me out, but eventually it let both of us play. Today, its back to kicking us out. Thanks for the replies.. I will just keep messing with the router.
Kevin

Most of these games require quite a few ports to be opened. Did you change ALL of them?

To be honest, I'm skeptical that most games would allow ALL their ports to be changed. It's one thing to change ONE port for the benefit of a remote access solution (RDP) or webserver, simple enough, but these games can have rather complex port requirements, including TCP vs. UDP, various port ranges, etc. It just seems to me it would be asking for trouble by the game developer to allow end users to make that many changes and get it all right in the process. Heck, most beginning gamers don't even realize there's any issue w/ ports and NAT routers to begin with! Of course, I could be wrong, but I remain less than convinced.

 

[Brian_tii]

Did you ever try what I suggested and not doing ANY port address translation? I know MW 2 will fail back to a state where to function in that scenario which I would expect to negate the need to have ports open. I know this cause my firewall doesn't support NAT and had to do static nat's to ensure I got the "best" possible game performance... but it did work before....

 

[Brian_tii]

ugh... I meant to say my firewall doesn't support UPnP... it of course supports nat...

 

[eibgrad]

Did you ever try what I suggested and not doing ANY port address translation? I know MW 2 will fail back to a state where to function in that scenario which I would expect to negate the need to have ports open. I know this cause my firewall doesn't support NAT and had to do static nat's to ensure I got the "best" possible game performance... but it did work before....

How does disabling NAT help? He has two PCs each requiring game access, but only one public IP. That’s the killer problem. Port forwarding is almost a trivial issue since it can be managed in various ways, either w/ port forwarding, DMZ, or UPnP. But all of that breaks down once you have a requirement for multiple PCs needing access to the same game behind the same router.

The only way to solve this problem is to either have multiple public IPs, OR, the ability to change ALL the ports, OR perhaps some game configuration which doesn’t need to support unsolicited inbound traffic (and undoubtedly will result in limited game play options).

 

[Brian_tii]

Well the idea wasn't to disable NAT entirely, just the static destination nat's to force the game into not NEEDING any direct inbound connections. The downside is that someone else always has to be host, which causes the user experience not to be nearly as good. This idea may (or may not) work since some may rely on UDP traffic on specific ports similar to IPSEC... Any outbound connections should be handled by the stateful firewall which hopefully will be able to keep track of it all correctly. Again, might work, might not... but basically make the game think it has no other options and it may adapt to what you have. Like I said MW2 on PS3 certainly can do some of this and even let's you know with the "NAT Type: OPEN, MODERATE, or STRICT" display when you go to play it online.

 

[eibgrad]

Well the idea wasn't to disable NAT entirely, just the static destination nat's to force the game into not NEEDING any direct inbound connections. The downside is that someone else always has to be host, which causes the user experience not to be nearly as good. This idea may (or may not) work since some may rely on UDP traffic on specific ports similar to IPSEC... Any outbound connections should be handled by the stateful firewall which hopefully will be able to keep track of it all correctly. Again, might work, might not... but basically make the game think it has no other options and it may adapt to what you have. Like I said MW2 on PS3 certainly can do some of this and even let's you know with the "NAT Type: OPEN, MODERATE, or STRICT" display when you go to play it online.

That's basically what I meant about a change in game configuration. You may be able to reconfigure the game to somehow not need inbound connections. But as I suspected and you suggested, you probably get into issues of game play, perhaps certain features become inaccessible. I can't imagine you're allowed to change NAT type w/o negative consequences.

So if the OP can make such changes and live w/ those limitations, perhaps it's worth a try. Not being a gamer, I just don’t know how common that type of option may be.

 

[Brian_tii]

Ahh gotcha, I missed that part in your earlier post. Unfortunately I'm not real sure how common it is either... just figured it was worth a shot.