Windows 7 - MTU Limit - Test and change your connection's MTU limit

An MTU limit that is set too high can cause fragmented packets and packet loss on your connection. This tutorial will explain how to test if your MTU limit is sending fragmented packets and will explain how to find what value you should be using.

1) Open an elevated command prompt and...

thank you!

Thank you so much for this...finally I can connect to Xbox Live through my tethered EVO. +Rep

Happy to hear it helped

Ok so i know that your optimal mtu size is not suppose to be under 1400 but mine is 900 what is going on here can anyone help me

Is that what you've set, or is that the default of it in Windows?

I have a D-Link DLG-4500 that allows the setting of the MTU and is set by default to 1500 (at max). My Windows interface connection was set to 1504. I used your tutorial to determine the appropriate MTU and it turned out to be 1476, with the extra 28 bytes that equals 1504. Should I decrease the value of the Windows interface to be equal to that of the router, and if not what problems could that cause?

Is that what you've set, or is that the default of it in Windows?

thats what i get when i do the mtu packet to like google and such i was trying to find my optimal through cmd prompt and i can't get above 900 or it says i have to defragment it more.

If it's too high then all you'll get is packet loss with your connection. Setting the correct MTU limit just offers a smoother connection. In a nutshell. You can decrease it to 1500 yea, it won't cause any problems.

What's your current setup for your connection i.e. do you use wireless, or wired connection etc?

Quote: Originally Posted by toussaint89
Is that what you've set, or is that the default of it in Windows?

thats what i get when i do the mtu packet to like google and such i was trying to find my optimal through cmd prompt and i can't get above 900 or it says i have to defragment it more.

What's your current setup for your connection i.e. do you use wireless, or wired connection etc?

I have a wired connection i wont use a wireless. I think it is just my ISP they are complete crap. I pay 70 dollars a month for 1.5Mb and i usually get 400-500Kb which is ridiculous, its the only thing i can get here. But, other then that idk what it could be at all.

mine was 1460 at its best i still kept getting 25% loss it was going back and forth with 0% loss and sometimes 50% loss and when i would switch to 1461 it was worst same with 1459 i ran each like 10 times before deciding which one was the best .
But i couldn't find one tha was 0% loss all the time ,is this normal?