Change the Maximum Transmission Unit (MTU) Size at Registry Guide for Windows

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Registry Home > Network > Protocols > TCP-IP

Change the Maximum Transmission Unit (MTU) Size (Windows NT/2000/XP) Popular

This parameter specifies the Maximum Transmission Unit (MTU) for a network interface. By optimizing the MTU setting you can gain substantial network performance increases, especially when using dial-up modem connections.

MTU stands for Maximum Transmission Unit and in basic terms, it defines the maximum size of a packet that can be transferred in one frame over a network.

Open your registry and find the key below.

Create a new DWORD value, or modify the existing value, called "MTU" and set it to equal the required MTU size in decimal.

Recommended Values

576 - Dial-up Connections

1492 - PPPoE Broadband Connections

1500 - Ethernet, DSL and Cable Broadband Connections

Restart Windows for the change to take effect.

Note: For Windows NT 4 the key is [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ Tcpip\Parameters]

Note: IP datagrams may span multiple packets. Values larger than the default for the underlying network will result in the transport using the network default MTU. Values smaller than 68 will result in the tranport using an MTU of 68.


(Default)	REG_SZ	(value not set)
MTU	REG_DWORD	0x000005dc (1500)


	HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\P...

Registry Settings

System Key: [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\
Interfaces\[Adapter ID]]
Value Name: MTU
Data Type: REG_DWORD (DWORD Value)
Value Data: Default = 0xffffffff

Related Tweaks

Optimize Internet Connection Speed (Windows 95/98/Me) Popular

>> Recommended Download - check, repair and optimize your registry now with Registry Mechanic <<

Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk.

Last modified: March 20, 2002

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