What is a DNS Server? A DNS (Domain Name System) server is a critical component of the internet that enables the translation of human-readable domain names into IP addresses. It acts as a phonebook for the internet, helping devices and computers find the correct website or service when a user types in a URL or clicks on a link.

Without DNS servers, users would have to remember complex numerical IP addresses for every website they want to visit, making the internet much less user-friendly. Instead, DNS servers take care of the behind-the-scenes translation and ensure that users can easily access the web.

DNS servers maintain a database of domain names and their corresponding IP addresses. When a user requests access to a website, the DNS server looks up the IP address associated with the domain name and directs the user’s device to the correct location.

Related Read: What is a DNS NS Record? 

Types of DNS Services

The most common types of DNS servers are:

Recursive DNS Server

A recursive DNS server is a type of DNS server that receives DNS queries from clients and then resolves them by forwarding them to another DNS server or server.

Authoritative DNS Server

An authoritative nameserver contains the definitive answer for a particular domain name. An authoritative name server can be configured to provide answers to queries different than what it receives from its upstream resolver.

Related Read: What is a DNS Record? | 8 Main Types of DNS Records 

Purpose of a DNS Server

A DNS (Domain Name System) server serves a vital purpose in the functioning of the internet. It acts as a database and directory, translating human-readable domain names into IP addresses so that users can easily access websites and online services. 

The main purpose of a DNS server is to enable users to access the web by typing in a simple and memorable domain name instead of having to remember complex numerical IP addresses.

In addition to enabling easy access to websites, DNS servers also help to distribute the load of incoming traffic, ensure redundancy and reliability, and protect against cyber threats. They maintain a database of domain names and their corresponding IP addresses and direct users to the correct location when a request is made.

In short, the purpose of a DNS server is to act as a bridge between human-readable domain names and technical IP addresses, making the internet more user-friendly and efficient for users worldwide.

Working of a DNS Server

Putting in a URL is the same as telling your computer to look up a certain IP address and establish a connection. 

To accomplish this, it makes use of the Domain Name System (DNS) server, which consists of several interconnected servers:

  • DNS recursive resolver
  • Root name servers
  • TLD nameservers
  • Authoritative nameservers

Here’s a general overview of how a DNS server works:

  • Domain Name Resolution: The first step in the DNS process is to resolve a domain name into its corresponding IP address. This is done by a client, such as a web browser or email client, when it needs to access a website or send an email.
  • Client Query: The client sends a query to its local DNS resolver, asking for the IP address of the domain it wants to access.
  • Local DNS Resolver: The local DNS resolver is responsible for checking its cache to see if it already has the information for the requested domain. If it does, it returns the IP address to the client.
  • Recursive Query: If the local DNS resolver does not have the information in its cache, it sends a recursive query to a root DNS server.
  • Root DNS Server: The root DNS server responds to the recursive query with a referral to the top-level domain (TLD) DNS server responsible for the TLD of the requested domain.
  • TLD DNS Server: The TLD DNS server responds to the query by referring to the authoritative DNS server responsible for the specific domain.
  • Authoritative DNS Server: The authoritative DNS server is responsible for maintaining the records for the specific domain. It responds to the query with the IP address of the domain.
  • Client Cache: The client cache stores the IP address of the domain it has looked up. The next time the client needs to access the same domain, it can use the cached IP address instead of going through the entire DNS process again.
  • Client Connects to Website: Finally, the client uses the IP address to connect to the website or server it wants to access, and the process is complete.

Failure of DNS Servers

Several potential causes of DNS server failure include loss of power, malicious hacking attempts, and hardware failure. When the Internet was young, problems with DNS servers might have serious consequences. 

Now, DNS has a lot of built-in redundancy, which is a huge relief. Most Internet service providers (ISPs) offer redundant recursive resolvers for their customers, and there are many copies of the root DNS servers and TLD nameservers. (Personal computer users may also employ public DNS resolvers such as Cloudflare’s Popular websites typically have many copies of their authoritative nameservers.

Some users may experience delays in the event of a big DNS server failure due to the volume of requests being handled by backup servers. Still, only a massive DNS outage would render a significant chunk of the Internet inaccessible. 

In 2016, when one of the largest DDoS attacks in history hit the DNS provider Dyn, this was a real occurrence. When you sign up for Cloudflare’s Managed DNS Service, you’ll also get DNS security measures designed to keep your server safe from assaults and other typical threats.

DNS Lookup vs. DNS Resolver

DNS lookup is a query to an authoritative name server for the IP address of a domain. On the other hand, the DNS resolver is software that implements the Domain Name System protocol and translates domain names into IP addresses.

The DNS protocol is currently based on TCP/IP and UDP/IP. The client sends a request to a name server via UDP or TCP. The server responds with an answer within seconds and can be used in any application that needs it.

The DNS resolver is responsible for translating human-readable URLs into numerical IP addresses that computers can understand. This service has many applications, including email delivery and web browsing.

The main difference between DNS lookup and DNS resolver is that while you can use the latter to find out whether a domain exists or not (as well as its IP address), you cannot use it to find out what type of information is hosted at that domain (for instance, if it’s an FTP server).

Final Words

What is a DNS server, you ask? It’s the backbone of the internet that allows us to access websites with ease. Simply put, a DNS (Domain Name System) server acts as the internet’s phonebook, translating domain names into IP addresses. Essentially, it’s a crucial part of the infrastructure that makes accessing online resources as simple as typing a word.