DNS is a naming system for mapping complex IP addresses with rememberable alphabetical names. This article will give you an explanation of the domain name system.
If there’s an existing system that has been masquerading the sophisticated and complex side of the Internet then it has to be Domain Name System. Without a Domain Name System (DNS) in place, it would almost be impossible for us to use web with a comfort and ease that we relish today. Inspite of DNS being so relevant to Internet (and all of us), most of the population that uses Internet doesn’t even know what DNS is all about.
What is DNS ?
“Domain Name System”, commonly referred as DNS is a hierarchical naming system for mapping complex IP addresses with rememberable alphabetical names, usually called Domain names. Every service or resource on the internet has a unique IP address associated with it. As IP addresses are 32 bit addresses (such as 220.127.116.11), they are extremely hard to remember, especially when every web resource or entity has a different and unique IP address assigned to it.
Solution to the Resolution problem
Domain Name System basically maps the IP address assigned to a web resource or a web based service/utility with an easy-to-remember alphabetical domain name. After the mapping is done, the same mapping information is passed across Name servers existing all over the web.
Name servers are those servers, which are primarily queried by web browsers(the application that end user uses to enter domain names/URLs) to carry out the process of Name resolution. Name resolution basically refers to the retrieval of IP address, which is mapped to the queried domain name.
Once the IP address is resolved, the web browser accesses that IP address and the end user gets access to the website he queried for.
Resolution by country (.uk, .uk, .cn, .in etc) or resolution by extensions (.com, .net, .gov, .biz, .org etc) is a part of the resolution process, which helps resolving the queried IP address faster.
More about Name Resolution
Name resolution is a sequential process. Before reaching out to DNS Nameservers, our web browser looks up the IP-Domain mapping into the Hosts file, located in our own system files. If the queried Domain mapping is not found in Hosts file, the DNS nameservers are queried and DNS resolution takes place.
It’s important to note that Web browsers always look up into Hosts system file before approaching DNS Nameservers for Name resolution. It also implies that if Hosts file has been wrongly configured(done intentionally by some unethical hacker) then the victim is sure to face serious trouble accessing internet.
In rare instances, Netbios is used as a name resolution technique. It is rarely used because it is referred only if both the Hosts lookup and DNS Nameserver lookup fail to resolve the IP address.This method attempts to map the netbios name, the user is trying to connect to with an existing IP address.