This post shows how to manually apply Windows Vista DHCP fix to play nice with others on enterprise networks.

This is for enterprise networks that use layer 3 switches or routers (mostly from Cisco) who have trouble getting their Vista connectivity rolling.

Vista DHCP Fix From Registry

  1. Click Start
  2. Type regedit in the Start Search box and click regedit in the Programs list
  3. If you are prompted for an administrator password, type in your password
  4. Locate and click on the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces{GUID}
  5. In this registry path, click on the (GUID) subkey that corresponds to the network adapter connected to the network
  6. On the Edit menu, point to New, and then click DWORD (32-bit) Value
  7. In the New Value #1 box, type DhcpConnEnableBcastFlagToggle and then press ‘ENTER’
  8. Right-click DhcpConnEnableBcastFlagToggle, and click Modify
  9. In the Value data box, type 1 and click OK
  10. Close the Registry Editor

Note: By setting this newly created registry key to 1, Vista will first try to obtain an IP address by using the BROADCAST flag in DHCP Discover packets. If the BROADCAST flag approach fails, Vista will then try to obtain an IP without using the BROADCAST flag.

Note 2: Microsoft have release a Vista DHCP fix it wizard at their support page for the topic.


That’s it. There’s your Windows Vista DHCP fix. Depending on your network infrastructure this may not be necessary. Hopefully you don’t have to go find a bunch of Vista machines after this.

Also, I’ve heard from a few people to remove the subnet mask from your router config, under default router (gateway). It seems crazy to me to modify your network devices based on an operating system that a small subset of users will use. Users mostly use XP and 7.

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