The Domain Name Systems (DNS) is the phone book of the Internet. Humans access information online through domain names, like nytimes.com or espn.com. Web browsers interact through Internet Protocol (IP) addresses. Domain Name Systems translates domain names to IP addresses so browsers can load Internet resources.
Each device connected to the Internet has a unique IP address which other machines use to find the device. Domain Name Systems servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as 2400:cb00:2048:1::c629:d7a2 (in IPv6).
Domain Name System (DNS) is a hierarchical naming system built on a distributed database for computers, services, or any resource connected to the Internet or a private network. Most importantly, it translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. Analogous to a network “phone book,” DNS is how a browser can translate yahoo.com to the actual IP address of the Yahoo web servers (22.214.171.124). In short, DNS translates names into IP addresses.
The 8 steps in a Domain Name Systems (DNS) lookup:-
1.A user types ‘example.com’ into a web browser and the query travels into the Internet and is received by a DNS recursive resolver.
2.The resolver then queries a DNS root name server (.).
3.The root server then responds to the resolver with the address of a Top Level Domain (TLD) DNS server (such as .com or .net), which stores the information for its domains. When searching for example.com, our request is pointed toward the .com TLD.
4.The resolver then makes a request to the .com TLD.
5.The TLD server then responds with the IP address of the domain’s name server, example.com.
6.Lastly, the recursive resolver sends a query to the domain’s name server.
7.The IP address for example.com is then returned to the resolver from the name server.
8.The Domain Name Systems resolver then responds to the web browser with the IP address of the domain requested initially.
Some important terms related with Domain Name System (DNS):-
•Domain: A Domain is any tree or sub-tree within the overall domain namespace.
•Root Domain: Root Domain is the root of the DNS tree. It is unnamed and is represented by a period (.).
•Top-level Domain: Usually top-level domain name is a two or three character name code that identifies the organizational or geographical status for the domain name.
Example, .com, .biz, .net, .org, .gov, .in, .au etc.
•Second-level Domain: A second level domain is a unique name of variable length assigned to individuals or organizations that connect to the internet. Example: myuniversity.edu. Here second level name refers to “.myuniversity”, which is assigned by InterNIC.
•Sub Domains: Large organizations can further subdivide its registered domain name by adding subdivisions that are represented by separate name portion.
Example: mcse.omnisecu.com, rhce.omnisecu.com
•Fully Qualified Domain Name (FQDN): The entire hostname with its domain suffix such as sys-102.gas.chevron.com is called a Fully Qualified Domain Name (FQDN).
•Domain Name Systems Zone: As shown in above figure, Domain Name Systems namespace is hierarchical. Administratively, each level or node in the hierarchy represents a potential boundary of authority for management of the name space. A Domain Name Systems zone is a portion of the global Domain Name System (DNS) namespace for which administrative responsibility has been delegated.
How Does the Domain Name Systems (DNS) Work?
The Domain Name System is a redundantly operated, hierarchical, and decentralised system for the administration of names. It shares out responsibilities and ensures the uniqueness of the names on the separate hierarchical layers. This is done through a tree-like structure, known as the “name space”. The tree’s “root” divides into various branches, the familiar Top Level Domains, such as .de, .net or .com. These branch out further into so-called Second Level Domains, and so on and so forth.
The DNS, however, does much more than just linking computer names to IP addresses. It can also be used for saving and retrieving further information about the services linked to a domain. A Domain Name Systems query is able to find out, for instance, which computer acts as the e-mail server for the domain concerned or what a domain’s name servers are called.
Domain Name Systems has a number of Advantages and Disadvantages:-
1.Generally Domain Name Systems is the only system in the entire world that can help you browse the internet. With the internet becoming an integral part of the society, it has increasingly become important that DNS Servers remain maintained. Without them, then the internet would not exist.
2.No need for memorizing IP addresses -DNS servers provide a nifty solution of converting domain or sub domain names to IP addresses. Imagine how it would feel having to memorize the IP addresses of twitter, Facebook, Google or any other site that you normally frequent on a daily basis. It would definitely be horrific. Its system also makes it easy for search engines to be able to categorize and archive information.
3.Security enhancement -DNS servers are an important component for the security of your home or work connections. DNS servers that have been designed for security purposes usually ensure that attempts to hack your server environment are thwarted before entry into your machines. However, it’s important to note that the word used is enhanced. This means that you will need other security measures put in place to protect your data, especially if it’s a large organization with tons of sensitive data.
4.Domain Name Systems servers have fast internet connections -People and organizations that use DNS servers can be able to take advantage of high connection speeds that are a key feature in some of these servers.
1.One of the main Disadvantages of the Domain Name Systems is the fact that its registry can only be controlled ICANN, a non-profit organisation with roots tied in one country. This challenges the concept of net neutrality and has been a widely propagated argument over the last three decades.
2.DNS queries usually don’t carry any information about the clients who initiated it. This is one of the reasons why DNS has been popular among hackers. This is because the server side will only see the IP address from where the query came from and which can at times be manipulated by hackers.
3.DNS servers are based on the principle of a slave-master relationship. This means that if the master server is broken or manipulated in any way, then it will be hard to access the web page or database that was hosted on the server. Hackers have also used this to their advantage. By targeting the server machine and making redirects to other pages, they have been able to find ways of phishing information.