How DNS Server Works and What Are Its Types?
The Domain Name System (DNS) is an essential component of the internet that allows us to access websites using human-readable domain names instead of IP addresses. In simple terms, DNS acts as a phonebook that translates domain names into IP addresses, enabling our browsers to find and connect to the correct web servers.
In this article, we will delve into how a DNS server works and explore its different types.
Understanding the Basics of DNS
When you type a website URL into your browser’s address bar, such as www.example.com, your computer initiates a DNS lookup process to find the corresponding IP address. This process involves multiple steps and interactions between various DNS servers.
Step 1: Requesting the Root DNS Server
The first step in resolving a domain name is contacting the root DNS server. The root server contains information about the top-level domains (TLDs), such as .com, .org, or country-specific TLDs like .uk or .fr.
Your computer sends a query to the root server, asking for the IP address of the TLD server associated with the domain extension you are trying to access.
Step 2: Contacting TLD DNS Server
Once your computer receives the IP address of the TLD server from the root server, it sends another query to that specific TLD server. For instance, if you are accessing www.com, your computer would contact the .com TLD server.
The TLD server provides information about which authoritative name servers handle requests for domains within that specific top-level domain.
Step 3: Querying Authoritative Name Servers
After obtaining information about authoritative name servers from the TLD server, your computer contacts one of the authoritative name servers responsible for the domain you are trying to access. These name servers store the DNS records for specific domains and can provide the IP address associated with the requested domain.
Step 4: Obtaining the IP Address
Once your computer reaches an authoritative name server, it sends a query requesting the IP address corresponding to the domain name. The authoritative name server checks its records and responds with the IP address of the web server hosting the requested website.
Types of DNS Servers
DNS servers can be categorized into different types based on their functionality and purpose. Let’s explore some commonly used types:
1. Recursive DNS Server
A recursive DNS server is responsible for handling queries from client devices like your computer or smartphone. When you type a URL into your browser, your device sends a request to a recursive DNS server.
This type of server performs all necessary DNS lookups on behalf of clients, navigating through multiple levels of DNS hierarchy until it obtains the final IP address.
2. Authoritative DNS Server
Authoritative DNS servers store and manage specific domain zone files containing DNS records for a particular domain or set of domains. These servers are responsible for providing answers to queries about their respective domains’ IP addresses or other related information.
When a recursive DNS server requests information about a domain, it contacts one of its corresponding authoritative servers.
3. TLD Name Server
Top-level domain (TLD) name servers are responsible for handling queries related to specific top-level domains like .org, .net, etc. They contain information about which authoritative name servers are associated with each second-level domain within their TLD.
When a recursive DNS server reaches a TLD name server, it can obtain the IP addresses of authoritative servers responsible for the requested domain.
4. Root DNS Server
At the top of the DNS hierarchy, we have the root DNS servers. These servers store information about all the TLD name servers.
When a recursive DNS server receives a query for a specific TLD, it contacts one of these root DNS servers to obtain the IP address of the corresponding TLD name server.
The Domain Name System (DNS) is a critical infrastructure that enables us to navigate the internet using user-friendly domain names. By understanding how DNS servers work and their different types, we gain insights into the complex process behind translating domain names into IP addresses.
Whether it’s the recursive DNS server handling client queries or authoritative name servers managing specific domains, each type plays a crucial role in ensuring smooth and efficient web browsing experiences.