Windows Vista can not obtain an IP address

[Nobleman]

Hello Everybody,

Whenever I connect a Windows Vista-based computer to a network. A router or other device that is configured as a Dynamic Host Configuration Protocol (DHCP) server is configured on the network does not support the DHCP BROADCAST flag.In this scenario, Windows Vista can not obtain an IP address.So can Anybody Please tell Me Why Windows Vista can not obtain an IP address from certain routers or from certain non-Microsoft DHCP servers .

[Spyrus]

Sounds like DHCP is not enabled on that machine or the DHCP service hasn't started.

[Big Fish]

You may have a corrupted TCP/IP installation (which is vital to enabling DHCP). It could also be a faulty network cable or a problem with your network card/drivers.

[Marco-D]

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 can not process the DHCP discovery packets.

[Nobleman]

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 can not process the DHCP discovery packets.

Ok i know How it is Caused. so Can We resolve it. And also my router does Not support DHCP BROADCAST flag.

[Marco-D]

Ok i know How it is Caused. so Can We resolve it. And also my router does Not support DHCP BROADCAST flag.

If you know the router or non-Microsoft DHCP server does not support the DHCP BROADCAST flag, you can set the following registry entry as follows instead of using the DhcpConnEnableBcastFlagToggle registry key.

HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Tcpip \ Parameters \ Interfaces \ (GUID)

Value name: DhcpConnForceBroadcastFlag
Value type: REG_DWORD
Value data: 0

Note A data value of 0 disables this registry entry. You can use this registry entry to prevent Windows Vista from using the DHCP BROADCAST flag. After you set this registry entry, Windows Vista never uses the DHCP BROADCAST flag.