What is DNS and DNS Server? A Comprehensive Guid

Estimated read time 7 min read

The internet has become a crucial part of our daily lives, whether for work, communication, entertainment, or education. However, many of us may not fully understand the technologies that enable us to browse websites, send emails, or stream videos. One such fundamental technology is DNS, or Domain Name System, which plays a vital role in making the internet more accessible and user-friendly. In this blog post, we will dive into the basics of DNS, what DNS servers are, how they work, and provide examples that illustrate its importance in everyday life.

1. What is DNS?

DNS stands for Domain Name System, which is essentially the phonebook of the internet. Just like you store phone numbers for contacts in your mobile phone, DNS helps store and match domain names (like www.google.com) to their respective IP addresses (like 172.217.3.110). An IP address is a unique identifier for a computer or server on the internet. However, remembering strings of numbers can be difficult, which is why DNS was developed to simplify access to websites.

Example:

  • Instead of typing an IP address like 192.168.1.1, you can type www.example.com in your browser, and DNS translates that domain name into the corresponding IP address. This process happens in milliseconds, so users don’t even notice it happening.

Key Takeaways:

  • DNS translates human-readable domain names into IP addresses.
  • This system allows users to easily access websites without needing to memorize numerical IP addresses.

2. What is a DNS Server?

A DNS server is a machine (server) that holds the database of domain names and their corresponding IP addresses. When you type a domain name into your web browser, your computer communicates with a DNS server to find the correct IP address for that domain. There are different types of DNS servers, each responsible for various stages of this lookup process.

Types of DNS Servers:

  1. Recursive DNS Server: This server receives the DNS query from your computer (or device) and, if it doesn’t have the information already stored, it starts querying other DNS servers to resolve the domain name to an IP address.
  2. Root Name Server: When the recursive DNS server can’t resolve the domain, it forwards the query to a root name server. There are 13 root servers globally, and these servers know where to find the Top-Level Domain (TLD) servers like .com, .org, etc.
  3. TLD Name Server: These servers store information related to the top-level domains, such as .com, .net, or .org. They help direct the query to the right authoritative name server.
  4. Authoritative DNS Server: The final stop in the DNS query, this server holds the actual IP address of the domain in question. It answers with the IP address and sends it back to your browser, allowing it to load the website.

Key Takeaway:

  • DNS servers are the backbone of the DNS lookup process, helping direct your computer to the right website by translating domain names into IP addresses.

3. How Does DNS Work?

The process of DNS resolution involves several steps, though it typically occurs so quickly that users don’t notice any delays. Here’s how DNS works in more detail:

Step-by-Step DNS Lookup Process:

  1. User Action: You type a domain name (e.g., www.example.com) into your browser.
  2. Recursive DNS Query: Your browser first checks its own cache to see if it has recently resolved the domain name. If not, it sends a DNS query to your Internet Service Provider’s (ISP) recursive DNS server.
  3. Root Server Query: If the recursive server doesn’t have the domain information cached, it queries a root server to find the location of the TLD server (e.g., .com for www.example.com).
  4. TLD Server Query: The root server directs the query to the TLD name server, which knows where to find the authoritative DNS server for the domain example.com.
  5. Authoritative DNS Query: The TLD server points the recursive server to the authoritative DNS server, which holds the IP address for www.example.com.
  6. IP Address Response: The authoritative DNS server returns the IP address for www.example.com to the recursive server, which then forwards it to your browser.
  7. Website Loading: Your browser now has the correct IP address and can load the website you requested.

All of this happens in the blink of an eye, typically in milliseconds.


4. Common Examples of DNS in Daily Use

Now that you understand the technical side of DNS, let’s look at how DNS affects your daily internet use.

Example 1: Web Browsing

When you type a domain name like www.facebook.com into your browser, DNS resolves that name to an IP address, enabling you to connect to Facebook’s servers. Without DNS, you would need to know the actual IP address, which is less convenient.

Example 2: Sending Emails

Email systems also rely on DNS to function correctly. When you send an email, the mail server uses DNS to find the recipient’s mail server based on their domain name. For example, sending an email to john@example.com triggers a DNS query to locate the IP address of the mail server for example.com.

Example 3: Mobile Apps

Many mobile apps, especially those that require internet access, rely on DNS to connect to the services they offer. When you open a social media app or use a navigation service, DNS works behind the scenes to route you to the correct servers for those applications.


5. Why is DNS Important?

DNS is crucial because it serves as the gateway between human-readable domain names and the machine-readable IP addresses that computers use to communicate with one another. Without DNS, the internet would be far less user-friendly, requiring users to remember IP addresses instead of simple domain names.

Benefits of DNS:

  • User-Friendly Internet: Simplifies access to websites by allowing users to use domain names instead of IP addresses.
  • Load Balancing: DNS can distribute traffic among multiple servers, ensuring that websites remain accessible even during high traffic.
  • Security Features: DNS can help filter out malicious websites by blocking certain domain names associated with spam, malware, or phishing.

6. DNS Issues and Troubleshooting

While DNS typically works seamlessly, users may occasionally encounter problems. Here are some common DNS issues and tips for troubleshooting them:

Common DNS Issues:

  • DNS Cache Poisoning: Malicious actors can tamper with cached DNS records, redirecting users to harmful websites.
  • DNS Server Down: If a DNS server is down, users won’t be able to access websites, as the domain names won’t resolve to IP addresses.
  • DNS Resolution Delay: Sometimes, the DNS lookup process may take longer than usual, resulting in slow website loading times.

Troubleshooting DNS Problems:

  1. Clear Your DNS Cache: Sometimes clearing your local DNS cache can resolve browsing issues. This forces your device to query the DNS server for fresh information.
  2. Change DNS Servers: If your ISP’s DNS servers are slow or unresponsive, you can switch to public DNS servers like Google DNS (8.8.8.8 and 8.8.4.4) or Cloudflare DNS (1.1.1.1).
  3. Restart Your Router: If you’re experiencing widespread DNS issues on all devices connected to your network, a simple router restart can sometimes fix the issue.

7. Conclusion

DNS is an essential part of the internet’s infrastructure, providing the translation between human-friendly domain names and the numerical IP addresses that computers use. It makes web browsing, email communication, and app usage easier for everyday users without them needing to understand the technical details. From accessing your favorite websites to sending emails, DNS quietly powers many of the online services we rely on daily.

If you encounter DNS issues, there are simple troubleshooting steps you can take, like clearing your DNS cache or changing DNS servers, ensuring that your browsing experience remains smooth and trouble-free.

By understanding how DNS works, you’ll be better equipped to appreciate the role it plays in your digital life and troubleshoot any issues that might arise.

İbrahim Korucuoğlu

The author shares useful content he has compiled in the field of informatics and technology in this blog.