The dns lookup stands for the strategy or the way the net follows when a user asks for some web page by typing it on the address bar. The dns lookup refers for the search of the domain name of the certain internet site. By way of example when the user offers the site name as Google, from its domain name (i.e. Google) the net searches the internet and find the IP address attached to it. In this way, the world wide web is able to give the user his or her essential web-site.

The step involves transfer of series of messages between the computer and the internet service provider and also between the internet service provider and the root server. The first step of the dns lookup system begins when the user types the domain name for the website on the URL bar. The computer checks for the domain name through caches weather it has been earlier visited by the user earlier or not. If the site has been visited, the caches help the computer in opening that site. But if the caches don't have the history of the website the dns lookup begins for the asked website.

Mechanism of dns lookup
The dns lookup involves the internet service provider and the root server. The computer asks the internet service provider to lookup for the site that has been asked by the user. The internet service provider in turn asks the root server to look for the IP Address of the domain extension and help in where to look for the site.

After the root server has informed about the IP address of the domain extension, the ISP checks for the entire domain with the help of the root server which is also called recursive name server due to its functions. The authoritative name server then helps the internet service provide to look up for the entire domain on the given domain extension.

The name with the authoritative server is given due t its function because it assists the ISP in reaching the end tail. This way the ISP reaches the webpage which has been requested by the finish user. For speeding up the complete method, there are caches placed at each level that enable the ISP to reach the IP address directly with no the enable of root servers. The dns lookup assists the ISP if the user visits the web-site regularly or has opened the website in near future. The caches remember the routes that have been followed by the computer system for the web site earlier plus the ISP straight routes towards the website.

Loopholes within the dns lookup
If there is a hat within the dns lookup process, the complete machine halts or the firewall crashes. The dns lookup method crashes and due to this it takes a extended time for the search as well as decreased efficiency is yet another trouble. One of the prevalent difficulties with dns lookup is faulty delegations within the dns sub domain which once again outcomes into reduced efficiency and speed with the world wide web.