Xbox 360 MTU error, serious problem please help!

[War Machine]

Hello everybody. I have come here in the hopes that someone can help me solve this problem. I posted this in the xbox 360 forums and got very little help which wasn't useful anyway. I will post the message that I orginally posted there so everyone can read about my problem

Ok here is my problem. Last week or so I went to connect to live and out of the blue it just won't connect and it starts giving me an MTU failed error. My xbox live has been working fine for around a year or so. I have my xbox hooked up with a wireless network adapter connected to a LINKSYS WRT54G v5 router which is plugged in directly to my ACTIONTEC internet modem. I called xbox about the problem and they told me my router was no longer compatible and I needed to update my firmware after it working fine for almost two years which doesn't make sense. So I called LINKSYS and did all the router updating and IT STILL WON'T WORK after xbox told me that was the problem. So here is a short list of things I have tried while on the phone with linksys,xbox and quest my internet provider. I have tried opeing ports, fowarding ports, updating firmware, changing to a static ip, manually entering information on my xbox, directly entering the ip on my modems DMZ and my routers DMZ. I have done just about everything to try and fix this problem and I have wasted about two weekends trying to get this to work. My next step is to completeley reset my actiontec modem and reinstall it again with the setup disk. I have been on the phone with about 6 diffrent people and the problem is still not fixed. Can anyone tell me if there is ANYTHING else that could be causing the problem a virus,something broken etc. They have told me its not a problem with my router since my laptop still works perfectly with the router and the xbox can connect to the router. Can someone please help me sort this out!!!

Also today 3-3-09 I upgraded my modems firmware and reset my router back to the settings that worked when I bought it and it still would not work. Please help!

[pabscars]

Have you tried going directly to the router or modem with an ethernet cable, and bypassing the wireless network adapter

[War Machine]

Yes I did try that and it did not work I still got the mtu error. I tried chaning MTU settings on the modem and there is no option to change that. What about chaning mtu settings on my computer?

[War Machine]

Can anybody out there help me out?

[pabscars]

Not being familiar with your particular equipment, but i take it you are rebooting the modem every time you connect directly to the xbox, and setting the xbox to auto,

i know that if you remove your router to try your xbox directly, then you need to reboot the modem and wait for 30 seconds for it to settle down, then switch on your xbox and try it then, sorry if youve tried this already.

Can you take your xbox round to a friends to see if they can connect to xbox live, or get a friends to bring theres to you, that way you could eliminate the console, modem etc.

Have you googled your mtu problem to see what suggestions come up.

[War Machine]

I didn't try resetting the modem after I plugged the xbox directly into it but I could try that again, it just takes so long to move everything into that area. I was also thinking about having a friend come over and try his xbox over the wireless connection. But when It comes down to it I think the problem is my modem. Is there anyway to change the MTU setting on a modem? When I go to my modem settings I seem to have options for most other things but not the MTU. What about totally resettting the modem back to orginial settings could that maybe fix my problem?

[pabscars]

I dont know about your modem (try posting its type and make etc) but on mine there is no facility to change the MTU value,

It might be beneficial to reset everything back to standard, if youve been messing with it, as long as you know what your doing, but i would be tempted to write down all the important info on a piece of paper should you need to input that info later.

One thing i forgot to ask, have you changed or altered anything recently on your setup, that maybe affecting or causing your problem.

Re: your modem, ive read and found out for myself, that whenever you plug a new piece of kit into your modem via ethernet, you must reboot the modem first, as the modem is only capable of one output at a time (that then normally goes to a router) and is then distributed to your network for eg xbox, pc, laptop etc.

So when you unplug your router to plug your console in direct, the modem still thinks its connected to the router, and wont connect to the console. Unless you reboot the modem first, then switch on your console and it should then connect to live.

If you then want to connect your router back again, then power down the modem and router, switch the modem on, wait for the lights to settle down, then switch on the router, wait for them to settle, then your console, pc, laptop etc may be switched on.

I,m no expert by the way, so cant give you much more info, have you tried another console or taken yours to a friends to try it on there network.

[smee init]

Hi this might explain it and help:

Maximum Transmission Unit (MTU)

One setting a router or gateway can influence is the Maximum Transmission Unit (MTU). The MTU determines the largest datagram than can be transmitted by an IP interface (without it needing to be broken down into smaller units). So what does MTU have to do with playing games? Read on…

What does MTU do on Xbox Live?

The MTU of your router or gateway must be greater than or equal to 1365. If it is less than 1365, you won’t be able to connect to Xbox Live.

How do I check my MTU size?

There are two ways. You can check your router or gateway manufacturer’s documentation for your device’s MTU setting. Or, you can let Xbox Live help you. With the latest update of the Xbox Dashboard, you can now determine if your MTU setting is too small for Xbox Live.

To see your MTU setting in the Xbox Dashboard

Select Xbox Live to sign in to XboxLive from the Xbox Dashboard.
From the Connect Status screen, press theY button on your controller.
Press the A button to see diagnostic information. Find MT: x, where xis your MTU test result of either 0 or 1. 0 means your MTU size is not 1365 or greater and it won’t work with Xbox Live. 1 means your MTU size is 1365 or greater and you’re good to go for Xbox Live!
What if my MTU size is not compatible with XboxLive?

If the MT value is 0, you have a router or gateway that is incompatible with Xbox Livebecause ofits MTU setting. You’ll need to change the MTU setting on your device. See your device documentation to accomplish this.

---------- Post added at 09:53 ---------- Previous post was at 09:46 ----------

This applies to both your router and modem if either of them have a MTU value lower than 1365 then you will get this problem so try the test connected directly to each one to determin which one is giving this error. I had the very same problem not long ago and it turned out to be my cable modem which was replaced and now works fine.

[Callumpy]

I got this MTU problem yesterday when i changed to a different router, dont know about your router but if you go into the config page you should be able to change the MTU, mines set to 1400