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You configure the Dynamic Host Configuration Protocol (DHCP) server service to set the default gateway address of a DHCP client computer to be the same as the IP address. After you do this, a Windows Vista-based client computer cannot connect to any off-link addresses.
This problem occurs because Windows Vista-based DHCP client computers configure the gateway address first. Then, the computers add the IP address to the computer. Therefore, the gateway address is configured on the Windows Vista-based computer as if it is the address of another computer.
When any network traffic must be sent to an off-link address, the Address Resolution Protocol (ARP) is used to connect to the gateway address. However, because the gateway address is the IP address of the Windows Vista-based computer, a response is not sent for the ARP request. Therefore, the network traffic is dropped.
Service pack information
To resolve this problem, obtain the latest service pack for Windows Vista. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
935791 How to obtain the latest Windows Vista service pack
The following files are available for download from the MicrosoftDownload Center:
For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
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To work around this problem, use one of the following methods:
Configure a gateway address on the network.
Manually delete the default gateway address, and then replace the gateway address on the computer.
Configure the DHCP server so that the server does not advertise a default gateway address. Instead, configure the DHCP server to advertise the IP address.
Note Include the subnet mask value of 0 for the IP address in this configuration.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Vista Service Pack 1.
If you configure the SwitchedNetworkFlag parameter by using Registry Editor, a DHCP client computer obtains a default gateway address that equals the IP address that the client computer receives. This behavior causes the client computer to use the ARP for all the IP addresses that are on the local subnet. This behavior is useful for switched networks that do not have a router. For more information about how to set the default gateway address of a DHCP client computer to its own IP address, click the following article number to view the article in the Microsoft Knowledge Base: