Manually added Default Gateway disappears upon reboot.
Null or empty line in registry key "DefaultGateway | REG_MULTI_SZ"
- Start Regedit
- Navigate to HKLM\System\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\
- Select CLSID of network adapter (you can identify your adapter by looking at the IPAddress registry Data field).
- Doubleclick "DefaultGateway" (You will see a list of all gateways that disappeared, especially if you've tried multiple gateways and rebooted a few times). Very likely the first line will be blank or empty. Remove this first empty line, click OK, exit regedit and reboot.