DNS is responsible for name resolution. When you point your browser to it points to a server on the Internet. How does that happen? As you are aware, all networked computers are assigned with IP addresses. But how do you access the Web page hosted in Google's remote machine by simply typing a name like go ogle. com?
That phenomenon is achieved using domain name resolution.

There are some servers on the Web called name servers (or DNS) that resolve certain names to corresponding IP addresses, like google.com to its corresponding IP address, in our case. So, we should have the IP addresses of the DNS servers (generally provided by the Internet service provider) handy so that we don't have to remember everyone else's when we browse the Web. When we point our browser to google.com, it consults one of these name servers to find out the IP address and thus load the Web page. But where do we configure the IP addresses of these name servers?

If your network is configured with DHCP, there is no need to specify the name server explicitly. For static IPs, it is, however, necessary. We enter the DNS servers' IP addresses in the letclresolv.conJfile. Mine looks like the following:

Note that you don't really need to use the DNS addresses provided by your ISP. For safety purposes, I use OpenDNS-the IP addresses are listed in the above snippet. You can learn more on why OpenDNS is a much safer bet at OpenDNS | Providing A Safer And Faster Internet.