What is DNS (Domain Name System) and How Does it Work?

If you've ever set up a website or managed a domain name, you've probably come across the term DNS. DNS, short for the Domain Name System, is an essential component of how the internet functions.

Whether you're a website owner, an aspiring web developer, or simply curious about the intricacies of internet connectivity, this blog post will equip you with a deep understanding of DNS and its pivotal role in maintaining a well-connected digital world.

So, let's jump into this fascinating realm where domain names translate into IP addresses and unravel the framework that makes the internet function.

What is DNS?

At its core, DNS is a hierarchical naming system that translates human-readable domain names, like hostwinds.com, into computer-readable IP addresses, such as 104.168.205.10. When you enter a domain name into your web browser, your computer sends a request to a DNS resolver, which then queries the DNS server hierarchy to find the corresponding IP address.

DNS Name Servers

The DNS hierarchy consists of four main levels of DNS servers, also known as name servers. Each of these servers plays a specific role in fulfilling DNS queries or lookups. Let's take a closer look at these name servers.

DNS Resolver

Also referred to as a recursor, the DNS resolver is a server typically operated by your internet service provider (ISP). It communicates with other name servers to help find and retrieve the requested information, such as a web page.

Root Name Server

Root name servers store information about top-level domains (TLDs) like .com, .org, and .net. They provide the resolver with the address of the TLD server to visit.

TLD (Top-level Domain) Server

TLD servers contain information specific to TLDs (e.g., .com, .net, .org). For example, the .com TLD servers store details about domain names ending in .com. They guide the resolver to the authoritative server where the domain name information is stored.

Authoritative Nameserver

Authoritative DNS servers store the IP addresses associated with domain names. They have the final say on which IP address corresponds to a specific domain name.

How DNS Lookup Works

Now that we have a basic understanding of name servers, let's walk through the process of how they collaborate to fulfill a client query through DNS lookup.

User Query

A user queries a page by entering or clicking a URL (e.g., hostwinds.com/blog) in their web browser (Safari, Chrome, Firefox, etc.).

Resolver's Journey:

The query is passed to the DNS resolver, which seeks to find the IP address of the requested domain (e.g. hostwinds.com). The resolver starts by querying the root name server for information about the TLD (Top-level Domain) server responsible for the requested domain (e.g., .com, .net, .org).

Finding the Authoritative Nameserver:

The resolver proceeds to the TLD server to obtain the IP address of the authoritative name server for the domain. The TLD server provides the resolver with the IP address of the authoritative name server hosting the domain name.

Requesting IP Address:

The resolver contacts the authoritative nameserver and requests the IP address associated with the domain. The authoritative nameserver responds to the resolver with the IP address.

Obtaining the IP Address:

Equipped with the IP address of the domain, the resolver returns it to the user's web browser.

Fulfilling User Query:

The browser contacts the IP address via HTTP request. The server hosting the IP then sends the requested content (e.g. hostwinds.com web page) to the browser for rendering.

DNS Record Types

DNS records are used to store information about domain names and their associated IP addresses. There are several different types of DNS records, each with its specific purpose. Here's an overview of some of the most commonly used DNS record types:

A Record: Short for Address Record, the A Record maps a domain name to an IP address (e.g., example.com -> 192.0.2.1).

Think of the A Record as being similar to your phone's contact list where Jane, John, and Jerry have a specific number associated to each of their names. Similar to how you tap Jane's name to call her number, the DNS system taps the A record to call the IP address of a domain name.

CNAME Record: Also known as "Canonical Name", CNAME Record  is used to point an alias domain, typically a subdomain (e.g. www.example.com) to a canonical domain, also known as the primary or root domain (e.g. example.com). When a DNS query encounters a CNAME record, it will follow the alias (e.g. www.example.com) and resolve to the IP address associated with the canonical domain name (e.g. example.com).

MX Record: The Mail Exchange Record specifies the mail server responsible for handling email for a domain.  For example, the MX record for example.com might specify that email should be handled by mail.example.com.

TXT Record: The TXT record is used to store arbitrary text data associated with a domain name. It's often used for domain verification or to store SPF or DKIM records for email authentication.

Common DNS Issues and Troubleshooting

While DNS is a critical part of how the internet works, it's not without its issues. Here are some common DNS issues and how to troubleshoot them:

DNS propagation delays: When you change the DNS records for a domain, it can take some time for the changes to propagate to all DNS servers around the world. This can lead to temporary connectivity issues for some users. The best way to deal with this issue is to wait for the changes to propagate fully.

DNS cache issues: DNS resolvers and browsers cache DNS records to improve performance. However, this can sometimes lead to issues if the cached records become outdated. To troubleshoot this issue, you can try clearing your DNS cache or flushing your browser cache.

DNSSEC configuration issues: DNSSEC is a security protocol that adds an extra layer of authentication to DNS queries. However, it can sometimes be misconfigured, leading to DNS resolution issues. To troubleshoot this issue, you can use a DNSSEC validation tool to check your DNSSEC configuration.

Best Practices for Managing DNS

Proper DNS management will ensure the seamless functioning and accessibility of your website. With the right approach, you can significantly enhance reliability, performance, and overall user experience. Here are a few best practices to follow when managing DNS:

Choose a Reliable DNS Provider: The foundation of effective DNS management begins with selecting a reputable DNS provider. Look for providers with a proven track record of high uptime and fast response times. A reliable DNS provider ensures that your website's domain resolution remains consistently available and responsive to user requests.

Implement DNS Redundancy for High Availability: Embrace the principle of redundancy by deploying multiple DNS servers. This redundancy strategy ensures that if one server experiences downtime or encounters issues, the others can seamlessly handle DNS queries. Particularly vital for high-traffic websites or those with mission-critical functions, DNS redundancy mitigates the risk of service disruptions.

Configure DNS for Optimal Website Performance: DNS plays a significant role in determining website performance. Choose a DNS provider that offers advanced features such as geolocation-based routing. This enables directing users to the nearest server based on their geographical location, reducing latency and enhancing website speed. Additionally, leverage DNS caching to store frequently requested DNS records, minimizing lookup times and improving overall reliability.

DNS Makes the World Wide Web Go Round

DNS serves as the backbone of the internet, ensuring that our digital world remains interconnected and accessible. With its collaborative name servers, DNS efficiently translates human-readable domain names into computer-friendly IP addresses, enabling smooth navigation across the vast web landscape. This introduction offers a foundation that will assist you in learning more about DNS management and deliver seamless user experiences.