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

The Domain Name System (DNS) is one of those behind-the-scenes heroes of the internet that you probably don’t think about until something goes wrong. The system translates domain names into IP addresses that computers use to find each other online. Without DNS, we’d be stuck memorizing those numbers when visiting websites. Imagine remembering the IP address for every site you want to see!  

In this post, we’re diving into what is DNS, how it works behind the scenes and why it’s so important. Whether browsing your favorite sites or managing your own, understanding DNS can help make your internet experience faster, safer and more reliable.  

What is DNS?  

Often referred to as the internet’s phone book, the domain name system or DNS, breaks the website address (URL) into segments and queries multiple servers containing those bits of information. Those servers are called authoritative name servers and are the foundation of DNS. 

DNS was created in the early 1980s to map domain names to IP addresses automatically.   

The string of numbers that makes up an IP address is easily understandable by a computer but more complex for people. Instead of memorizing copious numbers, you can recall a website by its domain name. DNS connects that domain name to the correct IP address.   

Thanks to DNS, when you want to search for something, you can type Google.com into your browser instead of 172.217.20.78. 

Frequently visited websites get cached in your system, but when your computer doesn’t know the IP address, it sends your query through DNS to find the correct name server. 

DNS and name servers  

Name servers are the servers that make up DNS. They hold the records of multiple DNS types and translate a URL into an IP address. DNS name servers are a critical component of how DNS works and they help direct traffic on the internet. 

Four types of name servers make up DNS:   

• Recursive (also known as resolver) server  
• Root name server  
• TLD name server  
• Authoritative server  

How does DNS work? 

DNS (Domain Name System) is often called the internet’s phonebook because it translates human-readable domain names into IP addresses that computers use to communicate. While it might seem like your browser instantly finds the website you’re searching for, there’s a lot of behind-the-scenes work happening across various local DNS servers worldwide. Let’s break down the detailed process of how DNS resolution works:  

1. DNS query begins  

When you type a URL (e.g., www.bluehost.com) into your browser, your computer must find the corresponding IP address to reach the correct web server. First, your device checks its local DNS cache to see if the DNS records for that domain have already been stored. If the website’s IP address is cached (from a previous visit), the browser will use that data to load the site immediately. If it’s not cached, the query moves forward in the process.  

2. Recursive DNS resolver  

The DNS query is sent to a recursive DNS server if the website is not cached. This server is typically managed by your Internet Service Provider (ISP) or a third-party service (such as Cloudflare or Google DNS). The recursive server’s job is to resolve the DNS query by finding the correct IP address associated with the domain name. The recursive query resolver first checks its cache. If the DNS query isn’t cached, it starts the search by contacting higher-level DNS servers.  

3. Root DNS server  

If the recursive query server cannot find the requested DNS client record, it sends the query to a Root DNS server. The root servers are the highest level of the DNS hierarchy and help direct traffic to the correct TLD (Top-Level Domain) server. The root DNS servers have the corresponding IP addresses for the TLD name servers (e.g., .com, .org, .net), but they don’t store full domain details.  

4. TLD (Top-Level Domain) name server  

Once the query reaches the root server, it points to the TLD name server for the domain’s extension (like .com, .org, .net). The TLD server knows the authoritative DNS servers for the specific domain you’re trying to reach. For example, if you’re looking for www.bluehost.com, the .com TLD server will direct your query to Bluehost’s authoritative server. The TLD name server helps direct the query to the domain’s authoritative server, which has the most up-to-date DNS records for that domain.  

Also read: Bluehost Launches New TLDs 

5. Authoritative DNS server  

The authoritative DNS server contains the DNS records that include the actual IP address of the website you’re trying to reach. This server responds to the query with the correct IP address associated with the domain name. For example, when you query www.bluehost.com, the authoritative DNS server returns the IP address of Bluehost’s web server, where the website content is hosted. 

What is a DNS cache?  

If there’s a website you frequently visit, it isn’t necessary to locate the IP address every time. DNS caching will store the data locally on your computer or can also be cached on the ISP’s servers. 

Before locating the IP address, your computer will check if the information is cached. If your computer already has the data, then it doesn’t have to access a DNS server to resolve the query.  

If you have trouble accessing a website or application, you can clear your DNS cache to remove outdated information. It can also be necessary to clear DNS cache data for security and privacy reasons.  

DNS types  

DNS records are essential components of the Domain Name System (DNS) that help to direct internet traffic, ensuring users can access websites, send emails and verify the authenticity of domains. While DNS helps translate human-readable domain names into IP addresses, it also stores several types of records, each serving a specific purpose. These records manage everything from website access to email routing and security. Some of the most common DNS record types are:  

• A records or Address Records, link your domain name to an IP address. This is the primary DNS type. Records are necessary for every website to ensure that when users enter your domain name, their browser can find the website by the IP address.  
• MX records or Mail Exchanger, set a mail server for your domain name. So, when someone sends you an email, it tells DNS where your mail is hosted. If you use email services like Google Workspace or Microsoft 365, you must set MX records to ensure proper email routing.  
• TXT records or TXT, are commonly used for verification and security. They include Sender Policy Framework (SPF) and Domain Key Identified Mail (DKIM) records. A TXT record helps identify your website as a trusted source for email systems. It helps prevent email spoofing and ensures that email services trust your domain.  
• CNAME records or Canonical Name, point one domain name to another. This is used to make variations to your website. If you’ve ever typed bluhost.com and ended up at bluehost.com, you can thank CNAME records. These records are useful when you want to have variations of your website or redirect one domain to another without changing the URL shown in the browser. 
• NS records or Name Server records, tell you the specific authoritative name server for your domain. It points to the server which houses your IP address. They are essential for delegating DNS management to another server or service provider, ensuring proper handling of DNS queries. 

Why is DNS important?   

The Domain Name System (DNS) is one of the fundamental building blocks of the internet, playing a vital role in ensuring that users can easily access websites, send emails and use online services. Here’s why DNS is so important:  

1. Simplifies access to websites  

DNS allows users to access websites using human-readable domain names (like example.com) rather than numerical IP addresses (like 192.168.1.1). With DNS, you can avoid memorizing complex IP addresses for every website you want to visit. Bluehost domains simplifies the domain management, ensuring seamless DNS configuration and optimal website accessibility for users around the globe. DNS translates domain names to IP addresses, making it easier for users to navigate the web.  

2. Ensures website accessibility  

Without a properly functioning DNS, users couldn’t reach websites. When you type a website’s domain name into a browser, DNS resolves it to the correct IP address of the web server hosting that site. DNS records (like A and CNAME records) ensure your domain points to the correct server, making your website accessible globally.  

3. Handles email routing  

DNS is crucial for the proper functioning of email services. MX records in DNS specify the mail servers that handle incoming emails from your domain. These records are necessary for emails sent to your domain to reach the correct server and you could miss important messages. MX records guide email traffic to the correct mail servers, ensuring your emails are correctly routed.  

4. Supports security features  

DNS also plays a role in online security. DNS records like TXT records are used for email authentication (e.g., SPF and DKIM), which helps prevent spam and phishing attacks. These records verify that an email sent from your domain is genuinely from you and not a malicious actor. DNSSEC (DNS Security Extensions) adds an extra layer of security to DNS, protecting against DNS spoofing and ensuring the integrity of the information sent through DNS.  

5. Improves website performance  

DNS resolution speed can affect how quickly a website loads. Caching DNS records at various levels, such as in local DNS resolvers or web browsers, helps reduce the time needed to resolve a domain name. Faster DNS resolution means users wait less for a website to load. DNS caching temporarily improves performance by storing DNS query results, reducing the need for repeated lookups.  

6. Enables flexibility and scalability  

DNS allows changing where your website is hosted without affecting your domain name. You can update A records or NS records to point to a new server or host and the changes will be reflected across the internet without users needing to know the new IP address. As your website grows, DNS enables easy scaling by pointing to different servers or content delivery networks (CDNs).  

7. Supports domain management and customization  

DNS allows for managing subdomains, so that businesses can create and manage different sections of their websites or services under the same domain. DNS subdomain management allows businesses to organize content and services while maintaining a cohesive brand identity.  

Security concerns with DNS  

DNS is a vital part of the internet, yet it is frequently overlooked, which makes it prone to security attacks. Some examples include:   

1. DNS reflection and amplification attacks can flood the DNS system and interrupt regular traffic from reaching an organization.   
2. Typo squatting is when hackers register domain names similar to other websites and phish for data from users.  
3. DNS cache poisoning diverts user traffic to malicious websites and servers, where users might divulge passwords or other personal information.   

Be aware of these threats and protect your website from any breaches.   

DNS eliminates the need for people to remember long strings of numbers to identify their favorite sites. For over three decades, DNS has kept the internet running by getting people where they need to go.   

Now that you know how DNS works, you need to ensure that your DNS records are correctly set up to guide people to your website. If you learn how DNS works, you can also help prevent suspicious behavior from harming your website. 

You’ll get a smooth experience for users if you review the various DNS types and ensure everything points to the correct location. 

How to improve your DNS performance   

Improving DNS performance is crucial for faster website loading times and a smoother browsing experience. Here are several strategies you can use to enhance your DNS performance:  

1. Use a faster DNS provider  

• Many ISPs have slow DNS servers, so switching to a third-party DNS provider can improve your DNS resolution times.  

2. Enable DNS caching  

DNS caching helps reduce the time it takes to resolve domain names by storing previously resolved DNS records locally. Caching can be done at various levels, including:  

• Browser cache: Browsers like Chrome and Firefox store DNS queries for quicker access. 
• Operating system cache: Operating systems typically cache DNS records via stub resolvers, speeding up the process for repeated requests.  
• DNS resolver cache: ISPs or third-party DNS providers cache records, making subsequent requests faster.  

Ensure that DNS caching is enabled on your server, device and DNS resolver.  

3. Use DNS prefetching  

• DNS prefetching is a technique that allows browsers to resolve domain names before the user even clicks on a link. This reduces the delay when the user visits the page. It’s particularly useful for websites with many outbound links.  
• You can enable DNS prefetching on your website by adding a <link rel=”dns-prefetch” href=”//example.com”> tag in the HTML header.  

4. Implement a Content Delivery Network (CDN)  

• A Content Delivery Network (CDN) can improve DNS performance by caching static content (images, scripts, etc.) at multiple edge servers across the globe. This reduces the distance between the user and the content, speeding up DNS resolution and delivery.  
• CDNs like Cloudflare often include DNS acceleration features to optimize DNS resolution for faster response times. Bluehost offers SiteLock, which helps you enhance both your website’s performance and security. 

Also read: Protecting Your Website From CyberThreats With SiteLock Security 

How Bluehost SiteLock enhances CDN performance 

Bluehost provides SiteLock, which boosts both speed and security when added to your CDN setup. With SiteLock’s CDN, you can enjoy unique benefits designed to enhance your website’s performance and protection. 

1. TrueShield firewall: SiteLock’s TrueShield firewall, bundled with the CDN, ensures that while your website’s static content is delivered at lightning speed, it is also shielded from potential threats like DDoS attacks, malicious bots and other cyber risks. 
2. Automatic access to CDN: With SiteLock’s Prevent and Prevent Plus plans, customers automatically get access to CDN and content acceleration features for free. This ensures that your website not only loads faster but also stays protected with the latest security features. 
3. Faster and safer browsing: By combining the power of TrueShield with SiteLock’s CDN, your website delivers an optimized, secure and fast browsing experience to visitors, while ensuring your site is continuously protected from attacks. 
4. Global reach and speed: SiteLock’s CDN offers content delivery from a global network of edge servers, ensuring your website performs optimally no matter where your users are located. 
5. Ongoing monitoring: SiteLock also includes performance monitoring, allowing you to track uptime and measure how effectively your CDN is performing while ensuring security threats don’t disrupt your service. 

5. Optimize TTL (Time to Live) settings 

• TTL is when DNS records are cached before they need to be refreshed. Setting an appropriate TTL can help strike a balance between performance and accuracy.  
• Shorter TTL: A shorter TTL ensures updated records are fetched for dynamic websites that often change (e.g., ecommerce sites).  
• Longer TTL: A longer TTL reduces the number of DNS queries and improves performance for static websites.  

6. Monitor and manage DNS load balancing 

• If you have multiple DNS servers or are using a DNS service that supports load balancing, ensure that your DNS records are evenly distributed across your servers. This will help prevent server overloads and optimize response times.  
• Consider using a Global Traffic Management (GTM) system that routes DNS queries to the nearest server or data center based on the user’s location.  

7. Use DNSSEC for security and performance  

• DNSSEC (DNS Security Extensions) not only improves security but can also indirectly improve performance by preventing DNS cache poisoning attacks, which can cause delays due to corrupted DNS data.  
• While DNSSEC adds a layer of security to the DNS process, it can also help when DNS data integrity is compromised, leading to smoother resolutions. 

8. Reduce DNS Lookups with caching DNS resolvers  

Each resource will typically involve a separate DNS lookup if your website has numerous external resources (e.g., fonts, scripts, APIs). Reduce the number of DNS lookups by:  

1. Using DNS caching resolvers: Configure your server to store DNS query results temporarily. This allows the server to reuse previously resolved domain information for multiple queries, reducing the need for repeated lookups. 
2. Minimizing external resources: Consolidate resources like fonts or scripts and reduce the number of third-party domains your website relies on. 
3. Optimizing time-to-Live (TTL) values: Adjust TTL settings to balance the freshness of DNS data with the benefits of caching. Longer TTL values reduce the frequency of DNS lookups for unchanged records. 

9. Regularly check DNS health  

• DNS monitoring tools can help you track the performance of your DNS servers and resolve issues before they impact website performance.  

10. Configure DNS for anycast routing  

• Anycast routing allows DNS queries to be answered by the nearest available server, improving speed by reducing the distance between the client and the server. Many premium DNS providers offer Anycast services to enhance performance and redundancy. 

Also read: How to fix DNS Server Not Responding error 

Final thoughts  

Optimizing DNS performance is crucial for faster website load times and a better overall user experience. You can significantly improve DNS resolution speed by choosing faster DNS providers, enabling caching and fine-tuning your TTL settings. Techniques like DNS prefetching, using a Content Delivery Network (CDN) and implementing DNSSEC can also help enhance your website’s performance and security. Regularly monitoring and managing DNS traffic will ensure that your site remains fast, reliable and secure.  

If you are Looking for a reliable hosting and domain management solution for your website? Bluehost offers an integrated suite of tools to streamline domain registration, DNS management and hosting. With our user-friendly interface and powerful features, Bluehost ensures your site is not only accessible but also performs at its best from day one.  

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