I have a xbox 360 that fails the mtu portion of the network connection. i have at&t dsl that is run through the phone jack to the router ( 2wire 2701hg-b) and from the router to the xbox. what do you suggest?

In order to connect to Xbox Live with a Wireless Modem and Router, you will need a Xbox 360 Wireless Adapter. You can get a Xbox Wireless Adapter cheap on eBay, or you can buy it Microsoft at Gamestop. http://www.gamestop.com/browse?nav=16k-Xbox+360+Wireless+Adapter
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To find your MTU Settings, follow these steps.
1. Click on 'Start'
2. Click on 'Run...'
3. In the bar, type CMD, and hit enter.
4. A black box should appear. Type "ipconfig" without quotation marks in the field.
5. Your IP Address, Subnet Mask, and Default Gateway codes should pop up.
6 Go to your internet browser and type you IP Address into the URL box.
7. You should find MTU settings, and you can set them to your desire.

An MTU is the largest physical packet size, measure in Bytes that a network is capable of transmitting.. If messages are larger than the MTU they are divided into smaller packets before they can be sent. All networks have different MTU's which the owner of the network set at what they want to set it at. 576 is a very common MTU if you connect through PPP. 1500 is the most common MTU for Ethernet connections. The Xbox Live system requires your network to have a certain Maximum Transmission Unit (MTU). MTU values are important to the performance of online games. If this test fails, you can adjust the MTU setting on your network router or equivalent device to resolve the problem. Xbox live requires the network you use to have a maximum MTU. This is key to online gamesing. If the MTU fails then you have to adjust the router you are using. If you cannot access the router to adjust the MTU the you will not be able to play online games.

Once you have all the wireless settings of the router, you are ready to connect the play station or the x-box to the wireless network.

X-BOX

On the x-box you will need to connect to the wireless network now.
Open the main Interface of the X-Box.

1. In the Xbox Dashboard, go to My Xbox and open System Settings.

2. Select Network Settings, Configure Network.

3. On the Basic Settings tab, select your wireless settings.

4. Select the name (SSID) of your wireless network. If your router isn't broadcasting your network's name, select Specify Unlisted Network and enter the name.

5. If your network has wireless security, enter your WEP or WPA key.

6. Try to connect to Xbox LIVE again.

Trouble connecting to the internet on X-box ,Play station or WII ?

You can try to reduce the MTU settings on the router. if the MTU on the router is set to 1500 then change the MTU to 1365. Also you will need to open the ports on the router.

For X-box port numbers are - 53, 80-88, 3074 .

reset it...look at back side of modem.....
and if it not works then contact your isp ...

Yes you can. My neighbor is piggy backing off my gateway 2wire router from att. He doesn't have any lag except for late at night. Other than that it rocks. Just set up your security.

ok well I found a fix but it may not be simple. anyway, i got my xbox360 to work off of my girlfriends laptop by feeding internet to the laptop from the cable modem via usb and then from the laptop to the xbox360 via ethernet. just right click usb connection in network connections and click sharing tab, then activate sharing and tell it to share connection with lan connection... you can also share through wireless if your xbox is wireless. I tried running all this through a dsl wireless router and a basic hub and both of them gave ip address and mtu errors... good luck

ther is no probs with ur xbox it will com on today

Browse to the router's setup page, should be 192.168.1.1 or 192.168.1.0 and log into it. You just have to change the MTU. Put it to 1500.
Once logged in to the router, go to :

Setup
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Basic Setup
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Wireless Setup
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Internet Connection Type
Connection Type = Static IP
Internet IP Address = 192.168.0.1
Subnet Mask = 255.255.255.0
Gateway = 192.168.0.1
Static DNS 1 = 192.168.0.1
Static DNS 2 = 192.168.0.1
Static DNS 3 = 192.168.0.1
STP = Enable
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Optional Settings (required by some ISPs)
Router Name = client-mode
Host Name = 2WIRE383
Domain Name = [empty]
MTU = Auto
Please remember to rate all users who assist you for free :)

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

Access the routers setup page by typing 192.168.1.1 (ip address of the router) on the address bar on IE.

then on basic setup page at the bottom part of the page you will see MTU normally its on auto,
to change the value set it to manual. ask your isp what is their prefferred value for the mtu you can go as high as 1300 to 1500.

MTU stands for "Maximum Transmission Connection". Some routers and/or network gateways are incompatible with Xbox LIVE, while others may be compatible but merely need to have a setting changed. If you compare your router to the list of routers at the following web address, you can confirm whether or not your hardware has been confirmed as compatible with Xbox LIVE by Microsoft:

http://www.xbox.com/en-US/support/connecttolive/xbox360/homenetworking/equipment.htm

Whether or not your hardware is listed as compatible, it would still be a good idea to check your instruction manual for the hardware you are using and see how (if possible) to change the MTU settings. Microsoft suggests that the MTU setting should be 1364. Using untested hardware or hardware not listed as compatible may still work, however, future updates to LIVE may suddenly make your hardware incompatible, as updates to LIVE and the Xbox console are made to work with the specifications of tested and listed compatible routers and gateways.