The Domain Name System ( DNS) is a conversion system that translates an Internet host name (domain name) into a specific sequence of numbers that, for each individual domain name, constitute an Internet Protocol ( IP ) address. An IP address is needed to route packets and coordination signals through the Internet grid and equivalent to a telephone number.
Each device connecting to the Internet has a special IP address used by other computers to identify the device. If the request is handled by one of the thirteen core servers known as the root servers, or a lower node on the Internet hierarchy that takes the brunt of the requests, the DNS is the key to fulfilling that request correctly if someone wants to reach a website. DNS servers remove the need to store IP addresses such as 192.168.1.1 (in IPv4) for humans or new alphanumeric IP addresses, such as 2400: cb00:2048:1::c629: d7a2 (IPv6), are more complicated.
DNS query starting from the computer. The computer knows the address of the nearest DNS "caching server" and passes the query there. This caching servers are usually run by individuals who provide internet access. The DNS resolution process requires the conversion of an into a computer-friendly IP address (such as 192.168.1.1), hostname (such as www.example.com). Each computer on the Internet is given an IP address, and that address is important to locate the right Internet device-like a street address is used to find a specific home.
The Computers can automatically learn the address of the available caching servers when connected to the network or have it configured statically by your network administrator. In order to understand the DNS resolution process, it is vital to learn about the various hardware components that a DNS query must move between. The DNS lookup happens "behind the scenes" for the web browser and involves no user computer intervention except the initial search.
In loading webpage there are 4 DNS servers involved:
The DNS recursor is a server that accepts queries by applications such as web browsers from client computers. Usually, in order to fulfil the client's DNS demand, the recursor is then responsible for making additional queries.
The main step to converting (resolving) human readable host names into IP addresses is the root server. It may be thought of like an index in a library that leads to multiple book shelves-it usually acts as a guide to other more precise sites.
Top level domain server(TLD) can be complicated. It is next step in search for a specific IP address, and it is last portion of hostname if its host (in example.com, the “com” is the TLD server.).
The Authoritative also the complicated server, which can be translate into its definition in specific name. If the record request will access by the authoritative server, DNS Recursor will receive the hostname back by IP address that have requested the initial request.
The recursive resolver is devices that reacts to a client's recursive request and takes the time to trace the DNS record down. It achieves this by making a number of requests before the requested document hits the authoritative DNS name server (or folds out or returns an error if no document is found). Fortunately, to monitor the records needed to respond to a client, recursive DNS resolvers do not always have to make multiple requests. Caching is a method of data persistence that, by serving the requested resource record earlier in the DNS query, helps short-circuit the needed requests. Can referred to figure below.
An authoritative DNS server is a The registry that currently keeps DNS resource records and is responsible for them. This is the server that will react with the queried resource record at the bottom of the DNS lookup chain, eventually allowing the web browser to request access to the IP address used to access a website or other web services. An authoritative name server can satisfy requests from its own data without having to ask any database, since it is the final source of truth for some DNS information. Can referred to Figure 2 below.