Web Hosting Talk : Other Forums : Computers and Peripherals : Problem with MTU

[guyellis1988]

Hi there, i know this isn’t really something web hosts deal with but it is do with tcp/ip specs and networking so I’m going to ask anyway!

I picked up an xbox360 the other week, its sat in my living room next to my media center pc. The media center PC has a d-link dwl-520+ wireless network card which in turn is hooked up to a standard 54mbps Belkin router.

Rather than pay over the odds for a MS wireless adaptor i decided i would just use ICS on the media center pc (especially since i intend to stream audio through it)

While configuring the connection the Xbox failed on the MTU test, after reading several KB articles I discovered the MTU needs to be no lower than around 1370 - that’s fine I thought ... XP defaults to 1480

So i hopped on the media center pc and at CMD prompt rang a: ping google.com -f -l 1400 (ping google with 1400byte file and don’t fragment packet)

I got back:

Packet needs to be fragmented but DF set.

which essentially means my XP media centers MTU is set lower than 1400

i tried the old higher-lower method and found it is set to 1281

I tried to change the MTU with drtcp but it didn’t change.

I checked the MTU on my router - 1480 (default)

I checked the MTU between my XP media center and my Xbox 360 - fine (above 1400 didn’t bother to check exactly where)

Essentially the MTU on my wireless card is set to 1281 and i need it set higher.


I thought perhaps it would be fixed by a re-install so i re-formatted the machine installed only the latest drivers from the d-link site, no software, no other drivers (other than those detected by windows)

repeated the ping google.com -f -l 1400 and ....

Packet needs to be fragmented but DF set.

I tried connecting the Xbox directly to the router (wired) and the MTU test passed straight away

If anyone has any ideas it would be appreciated, cheers!

P.S if you need clarification just post ... it’s not the easiest thing to explain on a forum!

Cheers.

[ALGORYTHM]

http://www.dslreports.com/drtcp

[guyellis1988]

I tried to change the MTU with drtcp but it didn’t change.

Think you missed that mate ;-)

[The Dude]

You have to reboot after you change the MTU setting (That part of the registry is only looked @ at bootup (@ least on 98se))

Good luck!

[guyellis1988]

Ive tried that, actually on 2k/XP based machines it only required a restart of networking, but even so i rebooted the whole machine.

Im wondering if it is my network drivers :/

time to buy a new network card i think!