Hello Dear Visitors, how’s the josh? I hope it always “High“. So Let’s jump into the Today’s Topic – what is DNS? and what is the use of DNS? before the explanation, I want to say something to all of you, that thing is – If anyone doesn’t want to get the extra knowledge in Computer Networking so please skip this post.
Full Description about DNS?
what is DNS?
DNS stands for Domain Name System. it sounds as it is the same. it is a type of mechanism to convert a numeric IP addresses to alphabetical(readable) naming. if we said that a company website address is 22.214.171.124 and its DNS name is bittutech.com so what will be the easiest thing for you to remember. I think your answer is bittutech.com. So that’s why the DNS mechanism is used to change the hard IP address into the efficient naming.
One more problem happened before the DNS is that if a network machine holds some information and any user wants to use that information, the first thing the user must know about IP address of the intended machine and second thing port number, it has to very difficult to remember but let assume that user knows the IP address and port number of the machine but the problem is that if the server machine has been replaced with another machine with IP address, it means IP address and port number both are changed. so now how to possible to reach the intended machine? solution is – everyone needs to be told the new IP address but this is a wrong or worst method. So now the efficient solution is – Consequently, high-level, readable names were introduced in order to decouple machine names from the machine addresses. In this way, the Company’s web server might be known as bittutech.com regardless of its IP address.
Nevertheless, since the network itself understands only numerical addresses, some mechanism is required to convert the names to network addresses.
Way back in the ARPANET days there was simply a file, hosts.txt, that listed all the computer names and their IP addresses. Every night, all the hosts would fetch it from the site at which it was maintained. For a network of a few hundred large time-sharing machines, this approach worked reasonably well.
However, now Today, we can’t accept this above mechanism to map our systems and their addresses, because we know that billions of system are connected with the Internet so it can be impossible to host all the systems. one more problem occurs, conflict the system name, this will an unthinkable result. so, we have developed a system that is DNS(Domain Name System) in 1983. it has been a key part of the Internet ever since.
Domain Name System mechanism uses a domain-based naming scheme and a distributed database system for implementing this naming scheme. it is primarily used for mapping host names to IP addresses but can also be used for other purposes. DNS is defined in RFCs 1034, 1035, 2181 and further elaborated in many others.
As briefly, DNS is used is as follows –
To map a name onto an IP address, an application program calls the library procedure called the Resolver, passing it the name as the parameter. The Resolver sends a query containing the name to a local DNS Server, which looks up the name and returns a response containing the IP address to the resolver, which then returns it to the caller. The Query and response messages are sent as UDP Packets(we will see in the next post). Armed with IP address, the program can then establish a TCP connection with the host or send it UDP packets.
Last Words : I hope you have to enjoy this post. please don’t forget to share your friends and classmates. we will come back with a full explanation about UDP Packets and after that full explanation about TCP connection, these are too major topic, which we will cover in the next post.
We should fight with ourself, only we knows, who we are?Prajjwal Singh