dns, what is dns, how dns works, how to use dns
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What is DNS, how DNS works?


What is DNS?

DNS, Domain Name System, is a database system that translates a computer's fully qualified domain name into an IP address.

Network resources are identified by numeric IP addresses, but these IP addresses are difficult for network users to remember. The DNS database contains records that map user-friendly alphanumeric names for network resources to the IP address used by those resources for communication. In this way, DNS acts as a mnemonic device, making network resources easier to remember for network users.

How DNS works?

Let's say you want to visit www.yahoo.com. Your computer hasn't already looked up www.yahoo.com since it was turned on. So your computer asks the DNS server of your ISP. The DNS server of your ISP first talks to one of thirteen "root" DNS servers. The root DNS servers answer questions at the highest level possible: the top-level domain. For instance, "who is in charge of DNS for the com domain?"

Now your ISP's DNS server knows which DNS servers are responsible for the com top-level domain. So your ISP's DNS server reaches out and contacts one of those servers and asks the next question: who is responsible for DNS in the yahoo.com domain? The response will list two or more DNS servers that have authority over the yahoo.com domain.

Finally, your ISP's DNS server contacts one of those DNS servers and asks for the address of www.yahoo.com, and hands the response back to your computer.

In real life, your ISP's DNS server will remember all of this information. That means that a typical user will get an immediate response when asking for the address of a frequently-visited site like Yahoo.

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