Vista Cannot Obtain IP Address From Some Routers or Non Microsoft Servers
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
To resolve this issue, disable the DHCP BROADCAST flag in Windows Vista which for some reason MS has decided to add and go against a 15 year standard.
To do this, follow these steps:
- Click StartStart button, type regedit in the Start Search box, and then click regedit in the Programs list. User Account Control permission If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
- Locate and then click the following registry subkey:
In this registry path, click the (GUID) subkey that corresponds to the network adapter that is connected to the network.
- On the Edit menu, point to New, and then click DWORD (32-bit) Value.
- In the New Value #1 box, type DhcpConnDisableBcastFlagToggle, and then press ENTER.
- Right-click DhcpConnDisableBcastFlagToggle, and then click Modify.
- In the Value data box, type 1, and then click OK.
- Close Registry Editor. 
1. ^ MS Knowledge Base 928233 - Retrieved on 26 March 2008
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