Yesterday I was helping a friend with his computer after a clean install of Windows 7. After each reboot, the Network and Sharing Center showed two active networks: the Work network – a wired LAN connection which was supposed to be listed – and an Unidentified Public network, which was not.
The result of having these two active networks was limited access, i.e. no Internet connection.
To temporarily resolve the problem, I could disable and re-enable the LAN card after each reboot in the Device Manager, which would cause the unidentified network disappear and the Internet connection to be restored. But the problem reappeared after each reboot.
The cause in my friend’s case (I discovered after half an hour of Google-aided research) was a secondary Default Gateway value of 0.0.0.0, which was showing up in the IPCONFIG readout before each re-enabling of the LAN card. I do not know the cause of this error, but it appears many users are reporting experiencing this problem in Windows 7 with several types of LAN cards and other networking hardware.
I was able to correct the problem on his Windows 7 PC with the following solution:
You must manually enter the Default Gateway in your Windows 7 Network Adapter’s IPv4 settings. The gateway is the IP address of your router. If you don’t know your router’s IP address, you can find it listed under Default gateway by opening the Command Prompt (Start > All Programs > Accessories) and typing IPCONFIG then pressing Enter. One listing may report the Gateway as 0.0.0.0; ignore this value and look for the one with four sets of numbers separated by periods. This will be something like 192.168.11.1. Write this number down; you’ll need it later.
Open the Network and Sharing Center by right-clicking on the network icon in the System Tray at the lower right-hand corner of your screen. Once there, click Change Adapter Settings on the left side of the window.
This will take you to a listing of your installed network adapters. Locate the adapter you’re using, right-click it and select Properties. In the Connection Properties window, select the Internet Protocol Version 4 line (shown above) and click the Properties button below.
Once in Properties, click the Advanced button, and use the Add feature under Default gateways to add your router’s IP address. Once entered, click OK and/or Close until you’re out of the network configuration windows.
Reboot your PC.
The problem should now be resolved.
You might also want to try updating your network hardware drivers. Some have reported that by updating the driver for their LAN card or Wi-Fi adapter that the problem was resolved – and it’s always a good idea to install the latest drivers for your computer’s hardware. Also check to see if your router (if you have one) is running the most up-to-date firmware (the router manufacturer’s web site is the best place to start).
Some installed software may also be the culprit. Adobe CS3 applications, along with some McAfee and Norton internet security software suites have been known to cause this networking issue.
Still No Fix?
If you’re experiencing this problem and no solution shown above works for you, please check the comments section below for other users’ suggestions. Many of them are excellent.
If you’d like to ask a question directly via email, or have a comment on this post, please feel free to email me.