It can occur on Windows 7 systems, particularly after a recent network driver update, that attempting to set a TCP/IPv4 Default gateway address along with a static IP address will fail. The IP address and Subnet mask will be correct but the Default gateway address will remain blank after saving the settings.
This is a known problem (https://support.microsoft.com/en-us/help/2555789/blank-default-gateway-may-occur-after-configuring-static-ip-address-fo)
There are two possible resolutions:
In some cases, once the machine is experiencing this problem, the static IP address, Subnet mask, and Default gateway must be reentered TWICE in order for the values to be saved correctly.
- Open the Local Area Connection / Internet Protocol Version 4 (TCP/IPv4) Properties dialog, and select “Obtain an IP address automatically”, and choose OK. From the Local Area Connection Properties dialog, choose OK.
- Reenter the Local Area Connection / Internet Protocol Version 4 (TCP/IPv4) Properties dialog, and select “Use the following IP address” followed by your specific settings. Choose OK and OK.
* Perform steps 1 & 2 AGAIN, even though the IP address appears to be displaying properly.
Open a command prompt as administrator and run the following netsh command TWICE, using the desired static address information.
- In the network and sharing center, note the name of the network connection that won’t save the gateway info. eg, “Local Area Connection 39”
- In the network and sharing center, set that connection’s ipv4 to “dchp” and close out of the dialogs
- In the start menu search box, type “cmd”
- Right click the “cmd.exe” command prompt result and select “Run as administrator”
- In the command prompt enter the text as shown below (using your settings) and press <return>
netsh interface ipv4 set address “Local Area Connection Name” static [IP address] [ subnet mask] [gateway address] and press <return>
netsh interface ipv4 set address “Local Area Connection 39” static 192.168.255.230 255.255.255.0 192.168.255.1 and press <return>
Note: This first command may return an error “Object already exists”
Repeat the same command line again and the command should succeed with no errors.