My parents in-law got their home router replaced by the provider with a crappy Zyxel wi-fi router. Besides the fact everything is working slower than before due to some internal firewall and management, one laptop having Vista on it (hmmm, it came with it) was unable to connect to the new network.

After spending few hours trying to connect, changing all the settings in the router, restarting the router like hell, I was about to reinstall the OS on that laptop. But as I never worked on Vista, I thought google-ing a bit might reveal similar experiences. And yes, I was so right… one of the first results was stating:

This issue occurs because of a difference in design between Windows Vista and Microsoft Windows XP Service Pack 2 (SP2). Specifically, in Windows XP SP2, the BROADCAST flag in DHCP discovery packets is set to 0 (disabled). In Windows Vista, the BROADCAST flag in DHCP discovery packets is not disabled. Therefore, some routers and some non-Microsoft DHCP servers cannot process the DHCP discovery packets.

The simplest thing you have to do is disabling Broadcast on your wi-fi card, by setting the REG_DWORD key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}\ DhcpConnForceBroadcastFlag to 0, where GUID is your wi-fi card ID.

Other options plus the description of the whole story is available here:

… and yes, the problem is solved in Windows 7.

Good luck!

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One Response to “Vista cannot get IP from some routers or some DHCP servers”
  1. Tomescu DragosNo Gravatar says:

    Vista a fost degeaba inca de la bun inceput. A fost doar un OS de test la trecerea catre 7. Parerea mea!

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