What is DNS (Domain Name System)?

Summary

In this video, Pooja from IBM explains the Domain Name System (DNS) in a clear and concise manner. DNS translates domain names like ibm.com into IP addresses, enabling computers to communicate over the internet. The video walks through how a DNS lookup works, detailing the roles of the DNS resolver, root server, top-level domain (TLD) server, and authoritative name server. Pooja illustrates how these components interact to retrieve and display the correct web page. The video is a great resource for understanding how web navigation happens behind the scenes.

Takeaways

• 🌐 DNS (Domain Name System) translates domain names like 'abc.com' into IP addresses, making it easier for humans to access websites.
• 🖥️ A domain name is any text string you enter in your web browser, like 'ibm.com' or 'google.com'.
• 🔢 An IP address is a numerical identifier used by computers to communicate on the internet, typically consisting of four sets of numbers.
• 📖 The DNS resolver acts as a phone book, matching domain names to IP addresses to bridge human communication with networking systems.
• 💾 The web browser first checks its cache memory for the IP address when you enter a domain name, speeding up the lookup process if found.
• 🔍 If the browser's cache doesn't have the IP address, the DNS resolver checks its own cache before forwarding the request to a root server.
• 🏢 The root server, at the top of the DNS hierarchy, doesn't store specific domain IP addresses but directs the request to the appropriate Top Level Domain (TLD) server.
• 🌍 There are multiple root servers placed globally, managed by 12 different organizations to ensure internet reliability.
• 📡 The TLD server (e.g., for .com, .net) forwards the request to the authoritative name server, which contains the specific DNS records.
• 🔙 The authoritative name server sends back the IP address to the DNS resolver, which then forwards it to the web browser, allowing access to the desired website.

Q & A

What is DNS?

DNS stands for Domain Name System. It translates domain names into IP addresses, allowing users to access websites using easy-to-remember names instead of numeric IP addresses.

What is a domain name?

A domain name is a text or string that users enter in their web browser to access a website, such as ibm.com or google.com.

What is an IP address?

An IP address is a unique numerical identifier assigned to each device on the internet. It consists of four sets of numbers and allows devices to communicate with each other.

How does DNS resolve domain names into IP addresses?

DNS uses a DNS resolver, which acts like a phone book. When a user enters a domain name, the DNS resolver matches it with the corresponding IP address, enabling the device to access the desired website.

What role does the DNS resolver play in the DNS lookup process?

The DNS resolver initiates the DNS lookup process. It first checks its cache for the IP address of the requested domain. If not found, it forwards the request to the root server and continues the process until the IP address is obtained.

What is a root server in the DNS hierarchy?

A root server is the top-level server in the DNS hierarchy. It doesn't store the specific IP addresses of domains but directs the DNS resolver to the appropriate Top Level Domain (TLD) server.

What is a Top Level Domain (TLD) server?

A TLD server manages information related to top-level domains, such as .com, .net, or .org. It helps the DNS resolver by providing the IP address of the authoritative name server for the requested domain.

What is an authoritative name server?

An authoritative name server contains all the DNS records for a specific domain. It provides the IP address of the domain to the DNS resolver, allowing the user to access the desired website.

What happens after the DNS resolver obtains the IP address?

Once the DNS resolver obtains the IP address from the authoritative name server, it stores the information in its cache and sends the IP address to the user's web browser, which then accesses the web server to display the website's content.

Why is DNS important for internet users?

DNS is crucial because it simplifies the process of accessing websites by translating easy-to-remember domain names into numeric IP addresses, which are used by devices to communicate on the internet.