What is a Domain name server (DNS) and How Does it Work?
It’s very common to type in the web address of a particular site on the browser to visit the site. Consider the Domain name server (DNS) as the phonebook of the virtual platform. The function of DNS is to translate human-readable domain names into machine-readable IP addresses.
⮚ Basics of DNS
Whether you are using a smartphone, a tablet, or a laptop to access the servers, you need the web address to find and communicate with the different sites.
Humans can access online information through domain names, like XXX.com or ABC.net. But the web browsers will interact via the Internet Protocol of IP addresses. The domain name system is responsible for translating the domain names into IP addresses.
Thus, without DNS, there will be no translation of the domain names to IP addresses. Therefore, the DNS is a critical element that aids in loading internet resources.
Each device that connects to the internet possesses a unique IP address. The other machines will use this address to locate the device. DNS servers prevent the need to memorize the IP addresses which can be complex numerical combinations or alphanumeric IP addresses.
⮚ The working mechanism of DNS
The process of converting the domain names into IP addresses is the task of the DNS resolution.
The IP address is the essential part to find the particular internet device. It is unique for each device. These addresses are functionally similar to the house address of an individual which is mandatory to locate the home of that person at a particular location.
When you want to load a webpage, the translation is necessary to convert the web addresses into the IP address.
For example, you type in the web browser XXX.com. DNS will convert this address into an IP address like 000.11.1.1. and this address will get you to the desired website. As the DNS resolution procedure happens in the background, it’s essential to learn more about them.
⮚ Types of DNS servers involved
There are 4 DNS servers involved while loading a web page.
- #1. DNS recursor : It is easy to compare the recursor to the librarian who receives the request to find a particular book from the accurate space in the library. The DNS recursor aims to receive the queries incoming from the client machines through the web browsers. The recursor will be then responsible for placing the additional requests for the satisfaction of the DNS query of the client.
- #2. Root nameserver : The root server is the initiation of the translation process. Its job is to begin the translation of the human-readable host names into the machine-readable IP addresses. It’s more like an index of the library that will point you to the various racks of books. In simple words, the nameserver is the reference to the more specific locations.
- #3. TLD nameserver : The top-level domain server or TLD plays a similar role as the specific racks for a particular type of book in the library. This is the second step in the Domain name server(DNS) resolution process. It will host the last part of the hostname.
- #3. TLD nameserver :#4. Authoritative nameserver : This is the final nameserver that is similar to the dictionary present in the book racks. this will be responsible for the translation of a specific term into its definition.The authoritative nameserver is typically the last stop in the entire nameserver query. When the authoritative server accesses the requested record, it will immediately return the IP address associated with the requested hostname. And then, it will give the IP address back to the DNS recursor once again, completing the chain.
⮚ Difference between recursive DNS resolver and DNS server:
The two above elements are critical aspects of the DNS resolution system. Both concepts refer to the group of servers or servers that are integral parts of the DNS infrastructure. But the individual elements perform different roles. And the elements reside in different locations too, inside the DNS query’s pipeline.
A very common way to differentiate the recursive resolver is that one is at the beginning of the DNS query, whereas the authoritative server comes at the end.
⮚ Recursive DNS resolver
Recursive resolver refers to the computer that responds to the recursive request from the client. It takes time to track down the DNS record. The process involves making a series of requests until it reaches the DNS nameserver of the authoritative segment.
There will be a time-out or other error if the request fails to track any record. However, the recursive DNS resolvers don’t need multiple requests to tracking down the records. They can respond to the client’s request with caching.
Caching is the data persistence process that will aid in short-circuiting the necessary requests. It serves the requested resources record in advance in the DNS lookup.
⮚ Authoritative DNS server
The authoritative DNS server is responsible for holding the DNS records. This is the particular server that will lie at the bottom of the entire DNS lookup chain. It will respond to the resource record associated with the query.
And this is the server that will finally allow the web browser to place the request for reaching the IP address leading to the website or web resources. The authoritative nameserver will satisfy the queries from the available data without raising another query for another source.
So, it’s good to conclude that it is the final source of truth when it comes to maximum DS records.
⮚ Steps of DNS lookup
- The user types the website’s address in the web browser and the query reaches the DNS recursive resolver.
- The resolver queries the DNS root nameserver.
- The root server responds to the resolver using the address of the Top-Level Domain server.
- Resolver requests the .com TLD
- TLD server responds with the IP address
- A recursive resolver sends a query to the nameserver.
- Nameserver returns the IP address to the resolver.
- The resolver responds to the web browser with an IP address.
- The complete picture of the system will now help you to perceive the significance of DNS in web searches.