Nat Problems with two xbox 360s, playing Halo 2 ... and can you change ports for xbox live ?

Posted on 2007-07-30
Last Modified: 2013-11-10
Open NAT and two xbox's.  Playing Halo 2.  Australia, ISP is Internode.

For background, if you don't know what I'm talking about when I refer to open NAT, you may want to refer to the following:

I have an understanding it has to do with UPNP, and perhaps the degree SPI in the NAT implementation.

I Know that port forwarding and putting the client in the DMZ will solve the issue if i only have one xbox....

I have two xbox 360s.

I am using a web excel (no name) AL-2108TC modem/router - supports UPNP, turned on.

Both xbox's report open NAT - when both are connected or each separately.

When only using one xbox we seem to have no worries - what you would expect with Open NAT.

But when we are using both xbox's at the same time we have problems connecting to some users : ( with one of the xbox's - which one can vary.  (sometimes cannot hear peoples voice and vis versa in pre game lobby, some people cannot connect to game)

Is there a way around this problem?

Can you change what port the 360 uses for xbox live that i can port forward to two different ports?  (due to the nature of p2p gaming - I'm not sure that this would work anyway).
Question by:activeckc
    LVL 16

    Accepted Solution

    Looks like you may not have an Xbox certified router. They have to perform UPNP in a specific way to make Xboxes work with them. Might be worth finding a friend who has a certified unit and borrowing it for a few hours to test.

    Author Comment

    I have already asked around ... I will buy one to test if necessary, but thought I would ask the question first.  

    I'm a bit worried that you can only fix this problem with two public IP addresses.  : (
    LVL 16

    Assisted Solution

    I have been googling it and a few people seem to have managed if the router properly supports UPNP. Just keep your receipt and your old router. If it still doesnt work, return it. :o)
    LVL 42

    Assisted Solution

    i have this issue.  i have two 360's and had problems with halo2.

    open NAT is a problem because you can only point it to 1 IP... not two.
    i tried to resolve this by creating a DMZ that included the range of my two console's IPs.  this also did not work

    what worked for me was to get a microsoft xbox live certified router.  it sounds crazy.. but yeah, that's what worked.  these routers are pre-configured so that you can use multiple xbox's and not have to dink around with their settings.

    i spent hours dinking with my older router's settings... and could get nothing to work.  the certified router was working as soon as i had it plugged in.
    LVL 2

    Assisted Solution

    I used to have the same problem with my first xbox.

    The way to get around this is easy, buy a certified router.
    Other way to get around this is as follows, my ISP provides me with 3 public ip's so, if yours is the same you're golden, you also need additional hardware
    You need to have a hub/switch and a router

    Setup your network like this: Modem -- hub/switch -- Router
    Connect one of the xboxes to the hub and the other to the router.
    Basically what youre doing is having each xbox on seperate public ip's.
    And as zephyr_hex stated above this is due to the fact that youre pointing to one public ip.
    By using the hub/switch youre assigning one pub ip to router the other to one of the xboxes.
    But this will only work if your isp provides you with multiple public ip's, and if you have a hub/switch, if not you can buy one for $10.

    Author Comment

    Thanks everyone for your help, I'm in the process of buying a certified router (as per list on, and I'll see how that goes.

    To be honest I'm not sure that the router itself will fix the problem - I'm thinking i might need the two public ip addresses.   I'll ring my ISP later today and see what they say on that front.

    Thanks for everyones input ... and I'll post back here when the new router arrives and I've had time to test it (putting in a couple new servers this week so it might not be till after the weekend).

    thanks again everyone for you input so far.
    LVL 10

    Assisted Solution

    You certainly do not need 2 public IPs. I have had many succesfull Lan parties with my XBox and XBox 360s. Also if you consider Internet Cafes that have PS2s and Xboxs, they share 1-2 public IPs for at least 2 dozen systems without a problem.

    Open NAT is the answer, but compliant OPEN Nat. The point of Open NaT is that on a network with multiple consoles, each console has a unique identifier by NAT. Try and look at it like this:

    XBOX 1 would send out IP IP Address:identifier
    XBOX 2 would send out IP IP Address:identifier
    XBOX 3 would send out IP IP Address:identifier

    Now someone else playing Halo 2, Far Cry or whatever is talking to someone on XBox 3. It used to be both parties required a correct router (I think that has now been changed), when they are talking to XBox 3, it will send back that Unique Identifier and the internal IP address of Xbox 3 that it is trying to communicate to. It now knows how to properly route back to 1 particaly machine in a multi-machine environment.

    Old NAT would simply listen for the Publci IP address and could only handle 1 machine at a time. The first machine that connected to Open nat, or that communicated in Chat, would receive back speech. In sense both/all the machines are fighting to be the only one to receive the data stream.

    This is the reason why in here and on the MS Forums people can't stress enough to purchase/use a certified router, or simply look for a firmware update to your existing router that may make it compliant.

    Just so you know also, I am runing about 12 consoles online right now from my Cable Modem, and there is no problems at all with multiple consoles online. And yes I do play Halo 2 still online.
    LVL 10

    Expert Comment

    LVL 4

    Expert Comment

    Frankly, I'd suggest reenable your NAT, don't set it to "open",

    Open these ports on your firewall: Ports 54, 88, 3074

    I'm not using a compliant router and am also not using port forwarding.

    My NAT does all the translations for my two 360s

    Expert Comment

    If you are going to have two 360s behind an IP address it is going to cause problems if specific ports are forwarded to one of the xbox's any traffic from peers could go to the wrong xbox. This would depend on wether the xbox without the benefit of being in the DMZ or having the necessary ports forwarded, started the given TCP session or not.  

    Forgive me but in "p2p gaming" one user is still selected to act as a server right?
    As far as I know, games even like Halo2 where you just get slapped together and play, IE nobody actively creates the session and lets others join, someone is still selected as the focal point for traffic IE they behave as a server and MUST be able to accept incoming TCP/UDP connections.

    So if you form a party and the wrong one of you gets selected as the host it could easily become a problem because the router doesnt care which xbox any incoming connections are for it simply follows the NAT/PAT rules  you have set up or sends the traffic to the internal address you set as the DMZ.
    Some routers seem to still work with 2 360s under these conditions others dont.

    Potential Solution 1 ($60): Shell out for a wireless adapter for the second 360 and ask your very cool /understanding neighbors if you can use their wireless connection. This work better for me than anything.
    Potential Solution 2 ($100+): Shell out for an xbox certified router.
    Potential Solution 3 ($200+ and $100+/month): Get a higher level of service with Comcast or FiOS that gives you multiple Internet IP addresses and a router that can handle a DMZ with multiple addreses. This may be free with the service or cost a lot.

    Author Closing Comment

    Just need a router that supports UPNP well.  The certified routers do it, as do some others .... i ended up with another one that did the job.  Thanks all.

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