Apparently some people (myself included) have reported that Windows Vista and Windows Server 2008 are loosing their default gateway settings after installing Service Pack 2 onto the machine. The basic symptom is that after putting in the default gateway everything works fine, until you reboot. The kicker is that after changing the default gateway the computer prompts you to reboot for basically no reason.
This can be because of a couple of issues.
- The default gateway has been saved with a blank line in the setting.
- The registry key that normally holds the default gateway setting doesn’t exist.
Now in my case I had this problem on a single virtual machine, but others have seen this problem on every VM they build, and some people have reported this problem on physical machines as well. In my case the VM that I saw this on had been cloned from a template, but every other VM which was cloned from that template didn’t show this problem, even though they are all running Service Pack 2.
Fixing this is a quick registry settings change. Because this is the registry don’t change anything unless you know what you are doing. And don’t call me if you delete something and your computer doesn’t work anymore.
Now that, that is out of the way…
Open RegEdit or RegEdit32 (your choice).
Navigate to HKEY_Local_Machine\System\CurrentControlSet\Services\Tcpip\Parameters\Interfaces
Under Interfaces you’ll see a bunch of folders with GUIDs as the name. Find the one that matches the NIC which is having problems (I was able to do this by matching the IP addresses up because I’ve got several NICs on the machine).
Now, if you don’t have the key DefaultGateway create it with a type of “Multi-String Value”.
Now double click on the key to edit the value. If your default gateway is in there, but there’s a blank line above it remove the blank line. If there’s nothing in the box, type in your default gateway for your network.
Click OK and close the registry editor. Reboot, and the next time the default gateway setting should stay.