A Definitive Guide to Domain Name System (DNS)

Domain Name SystemDomain Name System/Service or just DNS is a widely used in the internet and computer networks world. If you are thinking of venturing into maybe network security or ethical hacking, it is important to understand the exact manner in which a DNS operates because it is one of the key models in computer networks.

This post will give a step-by-step explanation of how DNS operates to make it straightforward and easy to understand even for readers that are coming across the topic of computer networks for the first time.

What Comprises a DNS?

A DNS is simply a computer networking procedure that helps to track a more relatable domain name.

For every network device whether it is a home PC, computer connected to a device, or a computer on the web, there is a special IP address attached to it. The IP address helps to launch a connection between the user and the server to facilitate data transfer between the two. The DNS has a very crucial role in the transfer whether you will be sending an email or accessing a website.
For instance, when you key in www.google.com in the address bar on your web browser, your computer will use the server to obtain the IP of Google’s server, which is 74.125.236.37. Once the server has fetched the IP address, a connection between your computer and the server will be established. It is only after this connection when you are able to view Google’s webpage loading on your device browser. The entire process is known as DNS Resolution.

It is not practical for users to keep a memory of every website that they need to access because there are thousands of sites on the Internet. The notion of a domain name was established as a result to give every website a unique identification to enable people to recall it.
Altogether, the IP address still remains the standard unit for internal communication for all the network devices. The DNS is needed in such a point because it does the work of translating the more relatable domain name to its matching computer-friendly IP address.

To simplify it for you, domain names are indicators aimed at users (humans) whereas IP addresses are meant for networking devices. DNS is the protocol that provides a connection between two. This explains why it is possible to access any website by just typing the IP address in place of a domain in the address bar. Maybe you should try it!

DNS Server Types and their Functions

DNS is a disseminated that is hosted on numerous computers on the web following a hierarchy format. There are different types of servers:

Root Name Servers

The root servers carry the highest level of any DNS hierarchy. The DNS servers included here have the full database of numerous domains as well as their matching IP addresses. Today, there are about 13 key servers with a global distribution and make use of letters such as A, B, C all the way to M.

Local Name Servers

Local servers are a representation of the basic level DNS servers and are possessed and controlled by (ISPs) or business organizations. Local Name servers can easily and frequently resolve used domain names to give matching IP addresses by giving a cache on the latest data. The cache receives regular updates and is frequently refreshed.

How Does a Domain Name Service Work?

Every time you key in a URL for instance http://www.google.com on the address bar of your browser, your PC will generate and send a special request to the specified local name server to determine the domain name of its matching IP address. The name of the query generated is DNS query. Additionally, that particular local name server receives the DNS query and begins verification to check if it has a corresponding name within its database. If the name exists, a matching response in form of an address is returned. If it does not exist, the server passes the query to a different server but in a higher level hierarchy.
This is an automatic process. It goes on until the query finds the destination server which has the corresponding name as well as IP address. The response generated (IP address) then follows a reverse order of the same chain back to your PC. In very rare instances, the local name servers may fail to reach the database containing the name that you are looking for, the DNS query will finally reach one of the several root name servers available to fetch the response.

Common Domain Name System FAQs

Here are the most frequent asked questions you will encounter as far as DNS is concerned.

How does a root name server fetch information on new domains?

The domain registrar is charged with the task of publishing and registering all the details in the root name server any time a brand new domain is generated or updated. It is only after registration with the root server that the information can travel down the DNS ladder and get sent to the other lower level local name servers.

What does DNS propagation entail?

Each time registration of a new domain or update of an existing domain takes place, details about the name is sent to all key DNS servers by default. This is to make the domain accessible from everywhere globally.
Normally, this whole process is referred to as the DNS propagation and it takes effect within 24-72 hours to complete.

How often are DNS servers updated?

There are no defined terms or criteria for guiding the frequency of updating the DNS servers. The frequency of updates is organization-based for instance depending on the ISP used for maintaining the server. Most organizations update their service every hour, while others do updates each day. Simply put, it is the decision of an organization to determine how often their DNS servers are kept up to date.

I trust that this post has helped you understand how DNS works in an increasingly credible and persuasive way.

However, if you have something that you’d like to add, feel free to leave your comment or question on the same in the comments below.

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