What is a Domain Name System (DNS)?

What is DNS?

The DNS or, Domain Name System, is a fundamental technology that transforms human-readable domain names, like www.google.com, into machine-readable IP addresses, such as 192.0.2.1. 

Each device on the internet has a unique IP address, and DNS servers facilitate communication between devices by mapping these addresses to corresponding domain names. This process allows web browsers to find and load internet resources efficiently.

Serving as the internet’s phonebook, this system enables users to reach websites without having to remember complicated numerical IP addresses. 

What is a DNS Server?

A DNS server is a specialized computer that maintains a database of public IP addresses and their associated domain names. Acting as the internet’s phonebook, it translates human-friendly domain names, like clouddefense.ai, into machine-readable IP addresses. 

When a user enters a domain name into a web browser, the DNS server locates the corresponding IP address, enabling the browser to retrieve the website’s data from content delivery network edge servers or origin servers. This translation process is crucial for directing users to the correct website efficiently.

How does DNS Work?

The DNS functions to translate human-readable domain names into machine-readable IP addresses, enabling web browsers to locate and access websites. This translation process, known as DNS resolution, involves several key steps and four types of DNS servers.

DNS Recursor

The DNS recursor, or DNS resolver, receives the initial query from the user’s web browser. Acting as a client on behalf of the browser, the resolver communicates with other DNS servers to find the correct IP address.

Root Nameservers

The resolver first queries a root nameserver, which manages the DNS root zone. The root nameserver does not know the IP address of the requested domain but provides a referral to the appropriate top-level domain nameserver.

TLD Nameservers

Next, the resolver queries the TLD nameserver, which is responsible for the specific domain extension (such as .com, .org). The TLD nameserver responds with the IP address of the domain’s authoritative nameserver.

Authoritative Nameservers

Finally, the resolver queries the authoritative nameserver, which holds the actual DNS records for the domain. The authoritative nameserver returns the correct IP address for the requested domain to the resolver.

Types of DNS Service

DNS servers have two primary types, one being authoritative DNS servers and the other is recursive DNS servers. Let’s learn more about each. 

Authoritative DNS Servers

Authoritative DNS servers hold the definitive records for domain names within their zones. They provide crucial information directly from the domain’s DNS records, making them the final authority in the DNS query process. 

These servers answer queries from recursive DNS servers by supplying the accurate IP address associated with a domain name. For instance, Amazon Route 53 is a well-known, authoritative DNS service that allows developers to manage public DNS names and update DNS records.

Recursive DNS Servers

Recursive DNS servers, also known as DNS resolvers, act as intermediaries between clients and authoritative DNS servers. They handle client queries by either providing cached DNS information or querying authoritative DNS servers to retrieve the necessary IP address. If the requested DNS record is cached, the recursive server responds immediately. 

Otherwise, it follows a sequence of queries to other DNS servers until it finds the authoritative server with the required information. Recursive DNS servers streamline the process, ensuring efficient and accurate DNS resolution for users.

DNS Server Not Responding. What does that Mean?

Encountering the message “DNS server isn’t responding” when you enter a domain name in your browser’s URL bar indicates a failure in the communication process between your device and the DNS server. This error can arise due to several reasons:

1. Unstable Internet Connection: A weak or unstable internet connection can hinder your browser’s ability to communicate effectively with the DNS server. If the connection drops frequently or is too slow, the DNS server may not receive or respond to the request.
2. Outdated DNS Settings or Browser: Your DNS settings or browser might need updating. Incorrect or outdated DNS configurations can prevent proper communication with the server, and an outdated browser may encounter issues processing DNS queries efficiently.
3. DNS Server Issues: Sometimes, the problem lies with the DNS server itself. Issues such as power outages at the data center hosting the server or technical glitches can disrupt the server’s ability to respond to queries.

How to Perform a DNS Lookup?

Performing a DNS lookup involves a series of steps that translate a domain name into its corresponding IP address. Here’s a detailed step-by-step guide for you, assuming no DNS information is cached:

Step 1 – User Query Initiation

• The process begins when a user types a domain name, such as ‘example.com,’ into their web browser. This query is sent from the user’s computer to a DNS recursive resolver.

Step 2 – Query to DNS Recursive Resolver

• The DNS recursive resolver, acting on behalf of the user’s computer, receives the query. If the resolver does not have the information cached, it proceeds to query the DNS root nameserver.

Step 3 – Query to DNS Root Nameserver

• The recursive resolver sends the query to a DNS root nameserver. The root nameserver, which manages the DNS root zone, does not know the IP address but directs the resolver to the appropriate Top-Level Domain (TLD) nameserver.

Step 4 – Response from Root Nameserver

• The root nameserver responds with the address of the TLD DNS server (such as .com, for example.com).

Step 5 – Query to TLD Nameserver

• The resolver then queries the TLD nameserver specified by the root server. For example.com, the query is sent to the .com TLD server.

Step 6 – Response from TLD Nameserver

• The TLD nameserver responds with the IP address of the domain’s authoritative nameserver.

Step 7 – Query to Domain’s Authoritative Nameserver

• The recursive resolver then queries the domain’s authoritative nameserver using the provided IP address.

Step 8 – IP Address Returned

• The domain’s authoritative nameserver responds with the IP address for the domain ‘example.com.’

Step 9 – Completion of DNS Lookup

• Finally, the DNS recursive resolver returns the IP address to the user’s web browser. With the IP address, the browser can request and load the desired website.

What is the Difference between Free vs. Paid DNS Server?

Choosing between free and paid DNS servers can be challenging. The table below highlights the key differences, helping you understand the additional features and benefits of opting for a paid DNS service.

Final Words

Understanding DNS is like uncovering the wonderful backbone of the internet! We’ve really come to value how this translation of domain names to IP addresses keeps our online world running smoothly. Not only does DNS boost our browsing experience, but it also enhances internet security and reliability. So, the next time you efficiently access your favorite site, why not take a moment to appreciate the amazing DNS system working behind the scenes to keep our digital lives connected?