It happens sometimes with your broadband connection that when you attempt to connect to Internet and fail to establish the connection, the Troubleshooter might show an error in the statement that the device, or DNS server is not responding.
One should keep in mind what to do when the broadband DNS server is not responding. There may be various reasons for this. The DNS server is down. To get over this, the first step is to try to change your broadband DNS to public DNS server of Google. Just follow the below sequential steps to overcome this problem.
Go to the start button or start screen (for windows 8). Search Control Panel. Click on it.
Click on Network and Internet. Then go to Network and Sharing center and click on the Change Adapter Settings option.
A dialog box appears. Choose the connection for which you want to change your DNS.
If you are required to give the administrator password, just type the password and carry on.
In the next step click on the tab named Networking and choose Internet protocol version 4 or version 6. Then click on properties.
Now Click Advanced and then the DNS tab. If the DNS tab contains any IP address of the DNS server, just erase them from that window. But before doing this don't forget to note down the IP addresses for any future purpose.
Then Click on OK.
Now click on Use the following DNS server addresses tab. If the Alternate DNS server or the Preferred DNS server tab contains any IP address then note them down for future purpose and then substitute those addresses with the IP address of Google's DNS server.
For IPv4: 126.96.36.199 and/or 188.8.131.52.
For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844
Select Validate Settings upon Exit on the bottom left corner of the dialog box. Then click on OK and close the window.
In the final step, restart your selected connection or restart the computer to check whether the given procedure worked or not.
The same steps for changing the DNS server could be found on Google's site.
Router Configured Systems
For router systems this is not the end of the problem.
First backup the settings and update the firmware of your router.
Secondly follow all the steps mentioned above to change your systemâs DNS server to Google's DNS server.
You need to enter the address in the router configuration that you entered in the preferred DNS server and Alternate DNS server of the IPV4/IPV6 properties in the control panel.
Then try installing OpenDNS for more help.
Go to start and search for CMD. It's Command prompt.
Open it and write IPCONFIG/ALL.
Then go to the network adapter and also note the physical address of the CMD screen.
Go to start screen.
Right click on the network adapter option and go to its properties.
Then select the configure option>advance>>network address>value.
Type the physical address noted earlier in the process.
Finally click OK and restart the system.
Prateek has written this useful article on how you could diagnose a Internet Connection problem, You can also get more information about broadband dsl connection here.