Configure DHCP Server for Unicast (Windows NT/2000/XP)

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

Configure DHCP Server for Unicast (Windows NT/2000/XP)
Category: Home > Network > Protocols > TCP-IP

This tweak can be easily applied using WinGuides Tweak Manager.
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By default, the Windows DHCP server sends all DHCP responses as IP broadcasts to the limited broadcast address (255.255.255.255). However, the DHCP server can be configured send to unicast responses by applying this tweak.

Open your registry and find the key below.

Create a new DWORD value, or modify the existing value called 'IgnoreBroadcastFlag' using the settings below.

Exit your registry, you may need to restart or log out of Windows for the change to take effect.

Note: Versions of the DHCP server prior to Windows NT 4.0 ignored the broadcast flag in client DHCP packets, and broadcast all replies.


(Default)	REG_SZ	(value not set)
IgnoreBroadcastFlag	REG_DWORD	0x00000000 (0)


	HKEY_LOCAL_MACHINE\CurrentControlSet\Services\DHCPServer\Parameters

Settings:

System Key: [HKEY_LOCAL_MACHINE\CurrentControlSet\Services\DHCPServer\Parameters]
Name: IgnoreBroadcastFlag
Type: REG_DWORD (DWORD Value)
Value: (1 = always broadcast (default), 0 = only broadcast if client requests)

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: September 24, 2002

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