Enable MTU Black Hole Detection (Windows 95/98/Me)

Registry Guide for Windows
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Registry tweaks, tricks & hacks to optimize, enhance and secure Microsoft Windows.

Enable MTU Black Hole Detection (Windows 95/98/Me)
Category: Home > Network > Protocols > TCP-IP

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Specifies whether the stack will attempt to detect Maximum Transmission Unit (MTU) routers that do not send back ICMP fragmentation-needed messages.

Open your registry and find the key below.

Create a new string value (or DWORD value for Windows 95) named "PMTUBlackHoleDetect" and set it to either "1" to enable detection or "0" to disable it.

Restart Windows for the change to take effect.


(Default)	REG_SZ	(value not set)
PMTUBlackHoleDetect	REG_SZ	1


	HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP

Settings:

System Key: [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP]
Name: PMTUBlackHoleDetect
Type: REG_SZ (String Value)
Value: (0 = disabled, 1 = enabled)

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: May 13, 2002

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