This article describes how to diagnose them NAT-type problems.

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With the release of the most recent Dashboard, Xbox Live users can analyze router problems on a more detailed level than they could in previous releases. Through the Dashboard’s Connect Status screen (Network Troubleshooter), you can access a new tool called Diagnostic Server. The Diagnostic Server performs various tests to determine whether your router:

•	It has an MTU setting that is incompatible with Xbox Live.
•	It handles ICMP port-unreachable packetsincorrectly.
•	It is a highly aggressive NAT-type router.

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NAT-type symptoms

With most NAT-type routers, you can connect to the Xbox Live service. However, if you, or other gamers you play, use an aggressive NAT-type router, you may experience some of the following symptoms:

•	You can play with one person on your friends list but notanother.
•	You cannot connect with a particular host in gamesessions.
•	You cannot hear voice during game sessions, even when youcan play without interruption.

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What is NAT?

NAT stands for “Network Address Translation.” Typically, home users obtain one IP address from their service provider, and then connect multiple devices to their home network. To share one IP address among many devices, a NAT-type router provides a popular solution. NAT makes it possible for each device to use the same IP address and connect to the Internet.

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NAT type classifications

Different routers have different methods for performing NAT. Therefore, they are classified by their NAT type as Open, Moderate, or Strict.

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How to determine if your router’s NAT type is causing problems

To determine if your router’s NAT type is causing any one of the symptoms described in the “NAT-type symptoms” section, you must know both your own NAT type and the NAT type of the gamer you are playing. To determine your own NAT type:

1.

Select the Y button on the ConnectStatus screen, and then press the A button tocontinue to the diagnostic read-outs.

2.

You receive the following information in theDiagnostic Server window: <Version #> NT: x NAT Type x=0  The APIcouldn’t be called (Couldn’t connect to determine NAT) x=1  Nat withMinimal port assignment, no port filtering (Open) x=2  Nat with Minimalport assignment, port filtering (Moderate) x=3  Nat with Aggressive portassignment (Strict) Note If you use Internet Connection Sharing (ICS) with Windows 2000Server or with Windows 2000 Pro, you receive a NAT type of 3.

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Compatibility table (by NAT type classification)

Use the following table, to determine if the NAT type classification for your router is an issue for you or the gamers you want to play.

	TO OPEN	TO MODERATE	TO STRICT
FROM OPEN	YES	YES	YES
FROM MODERATE	YES	YES	NO
FROM STRICT	YES	NO	NO

For example, you might want to host the latest Xbox Live title, and you verify that your router’s NAT type is “Open.” Using the table, you can know that your router’s NAT type will not prevent your friends (who may also be using a router) from finding your session, hearing your voice, and enjoying a great gaming experience.

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