Need to change MTU size in Vista

**Caiden** · 03-06-2009

I work on Windows Vista x32. What i need is to set the MTU size so that i get network app to work. Actually i need to decrease the size of MTU. It will be better if there way of registry for doing the same rather than any utilities. Please help. Thanks..

**SalVatore** · 03-06-2009

MTU is the maximum IP packet size in bytes, that can be transmitted over the underlying network.The default and maximum PPPoE MTU size is 1,480 bytes. With some Internet service providers (ISPs), you may have to reduce the MTU size of a PPPoE connection to a value between 1,400 and 1,480. Do not set an MTU size smaller than 1,400.Anyways, to change the size of MTU, go through this simple steps:-

1. Open Command prompt from the Start menu and navigate to the following folder:-

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\<AdapterID>

2. Now create a new Dword value key by right clicking and name it MTU.

3. Set the value 1400 for this key, as it is the minimum value that Microsoft recommend.

Close the registry and reboot the system to effect the changes. Thats it.This sets the MTU for that particular network adapter.

**Devasis** · 03-06-2009

Windows accepts and uses the MTU size that the adapter reports even when the MTU size exceeds the usual MTU size for a particular media type. You can change MTU size also if you navigate to HKEY_LOCAL_MACHINE \ SYSTEM\CurrentControlSet \ Services \ Tcpip \ Parameters \ Interfaces you can set the MTU for each protocol within the connections, or add in the key "MTU" as REG_DWORD for each if they don't have them.

While most of time MTU never has to be changed from the default values there are instances when you need to alter the MTU sizes to fix certain network performance issues.