Enable/Disable response to ICMP Type 17 address request messages in local network

Networked Computers can send ICMP Type 17 messages to know the subnet mask of the local network. Only hosts configured to be routers or gateways can respond to these messages. By default Windows hosts do not respond to ICMP Type 17 (Address request) messages as restriced by RFC 1122.

However, at any time you want to make your Windows server or PC to respond these messages then this can be done from Windows Registry.

This applies to Windows Server 2008, Windows Vista, Windows XP, Windows Server 2003 (if enabled) and Windows 2000.

The following procedure to edit the Windows Registry should help you allow/disallow Windows hosts to responding to ICMP Type 17 messages.

This applies to Windows Server 2008, Wi

ndows Vista, Windows XP, Windows Server 2003 (if enabled) and Windows 2000.

1. Click Start -  Search and type “regedit”. This launches the WIndows Registry.

2.  In the registry, navigate to the following registry key

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]

HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Services
\Tcpip
\Parameters

3. In the right pane, right-click and select New – DWORD (32-bit value) and set its name as “EnableAddrMaskReply” and set its value as “1″ to enable responding  to ICMP Type 17 Address request messages. Should you like to disable this  at a later time, set it “0″ (default) or simply delete the this key.

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