If you know that your default gateway is missing, then you’re probably trying to connect to your router, or fix a PC or laptop that won’t connect to the internet.
It also means you’ve probably tried to use the Command Prompt to get the default gateway by running the command: ipconfig /all
Regardless of whether those assumptions are correct or not, here’s how to go about fixing the problem.
Why is my default gateway blank?
There are a couple of reasons. First, it could be because the laptop or PC has been set to use a static IP address. Second, it could be a problem with your router or any other network hardware. Let's address these in order.
Windows IP address settings
To check your IP address settings, open the Control Panel and navigate to Network and Internet settings, or search for Network and Sharing Centre.
Whichever version of Windows you’re using, you need to track down the option to ‘Change adapter settings’.
The path to it (in Windows 10) is Control Panel > Network and Internet > Network Connections.
You’ll see a list of network adapters. Identify the one that is being used to connect the machine to your network, right-click on it and choose Properties.
In the list, scroll to find Internet Protocol Version 4, click on it and then click the Properties button.
Another window will open. Check the options as shown below: Obtain an IP address automatically and Obtain DNS server address automatically.
Click OK, then Close on the previous window. You may have to restart Windows for the changes to take effect.
This may solve the problem, and when you next log in you might well have an internet connection. You can also re-run ipconfig /all in CMD.exe to check that you now have a default gateway address.
That address should be the IP address of your router, which itself should be set to act as a DHCP server, which means it will automatically hand out IP addresses to devices on the network which are set to ‘obtain an IP address automatically’,
Is there a problem with my router?
If the solution above doesn’t help, it could be that your router isn’t working properly, or that there’s an issue with another device on your network.
You’ll know there’s a problem because when you run ipconfig /all, you’ll see that your computer has an IP address in the range 169.254.x.x.
Effectively, this means it hasn’t been able to get an IP address from your router, and it won’t connect to the internet.
If this is the case, first try rebooting your PC, and also your router.
The next step is to connect to your router from a PC that’s working (i.e. can actually talk to your router) and make sure everything looks ok. An extreme option is to factory reset your router, but before you do this, be sure to save the current configuration unless you’re happy to change settings manually and, potentially, re-enter your ISP’s details including your username and password.
Before you do reset your router, check if there’s any other network devices between your laptop or PC and the router. For example, you might be using a wireless bridge, or powerline network adapters.
Try restarting these, too, or moving your computer close to your router and connecting it directly, either via Wi-Fi or with a network cable.