On most home networks your DNS servers are being sent to your computer and other devices through a protocol called DHCP. This is Dynamic Host Configuration Protocol. The basic premise of DHCP is to allow multiple devices to connect to your home network through your router. By using this protocol the following happens:
A local area network Internet Protocol address is assigned to the computer automatically for Network Address Translation (NAT).
Domain Name Servers (DNS) are sent through the local gateway (the router) to your computer.
By using a NAT gateway through your router, you are able to see other computers and devices on your Local Area Network (LAN) network. This is how you can share files from one computer to another. You are also able to retrieve the DNS for things like websites. Just by making it here, that means you were able to pull down the IP address for "windows7forums.com", so in most instances DNS is working.
However, you may be having intermittent DNS outages. Most home routers do not have self-contained DNS servers. Your router is likely pulling down DNS information directly from your ISP. As a result, if your ISP's DNS servers become faulty, you will not be able to resolve hostnames or obtain DNS information for IP addresses.
Here is what you can do to temporarily solve this problem:
Manually set your DNS settings in Windows
In Windows, go to Start -> Search -> View Network Connections
Locate your "Local Area Connection" and right-click on the icon to navigate to Properties
Double-click on Internet Protocol Version 4 (TCP/IPv4)
Retain "Obtain an IP address automatically"
Check off "Use the following DNS server addresses:" and enter:
Preferred DNS server: 8.8.8.8
Alternate DNS server: 208.67.222.222
Explanation: These DNS servers are run publicly, and are generally extremely reliable. They are designed for users who are having difficulty obtaining proper DNS over the Internet. The first preferred DNS server is
Google's public DNS server. The second is run by
OpenDNS.
The better solution is to log into your router and plug these DNS settings directly into the router. This will ensure that you do not have connectivity issues with your local area network (LAN). That is, if you want to share printers off Windows or connect into other computers using Remote Desktop Connection, or even share music, you may have difficulty by manually inputting these settings. Few routers fully support Windows networking when manual DNS server addresses are entered in Windows. You may be cutting your computer off from the private network, but ensuring that you always have reliable DNS. What I would recommend is getting into your router and applying these same settings in the "DNS" area of the router. It is commonplace for a network technician to diagnose and solve networking issues this way. But it is also difficult for home users. That is why overriding your router's DNS settings in Windows is probably not a bad idea, especially if you keep having connection difficulties.
Ultimately, your ISP is probably running some shoddy DNS servers. This is especially the case if it is happening a lot. Alternatively, it could actually be the network card on your computer, but this is extremely rare. Another possibility is that it is the router itself. But 9/10 times it is the ISP's crappy DNS servers causing mayhem. The best option would be to set Google and OpenDNS as DNS servers in your router and continue to use DHCP assigned DNS. Since every router is different, giving you instructions on how to do that will not be easy. But a quick call to Cisco-Linksys support, D-LINK, or NetGear may help you in that area.
Try these settings: They are proven to work to correct this type of problem.