DNS: The Internet's Address Book

ELI5

Imagine you have a whole room full of toys. It is very organized, every toy has a name and there's so many that it can be hard to remember where they all are. When you want to play with a toy, instead of remembering where each toy is in the room, you ask your friend. He's very organized and remembers everything, he tells you exactly where to find the toy you want to play with!

In the world of computers, internet, and networking, there are billions of websites and each one has a very specific group of numbers called an IP Address, which is like the toy's name. Instead of trying to remember all those numbers, we use the Domain Name System or DNS, which is like your friend, to help us find computers by their names.

So, when you type a website name into your computer like "www.google.com", your computer asks the DNS, "Hey, where can I find this website?" and just like your friend, the DNS says "Oh, you can find it at this specific spot", then you computer knows how to find the website you want!

101

Whether you're navigating the expansive internet or your local network, the Domain Name System(DNS) plays a critical role in translating human-friendly domain names into computer-friendly IP addresses, simplifying the way we access resources and devices.

Imagine yourself in a bustling city, each building with its unique address, much like websites on the internet with their IP addresses. Just as google maps helps you find your way, DNS acts as the internet's address book, translating memorable domain names (like google.com or facebook.com) into the corresponding IP addresses.

But DNS isn't confined to the global internet alone; it extends its reach into local networks, like those found in homes, offices, or schools. In these environments, DNS serves a similar purpose but on a smaller scale.

Within a local network, there's typically a DNS server, often provided by the network's router or a dedicated server. This local DNS server maintains a database of domain names and their corresponding IP addresses for devices within the network.

When a device on the local network wants to communicate with another device by name, it sends a query to the local DNS server. This server then checks its database for the corresponding IP address and responds accordingly. To improve efficiency, DNS servers often cache recent query results, speeding up subsequent requests and reducing the need to ask other DNS servers for the same information again.

If the local DNS server doesn't have the requested information (for example, if a device wants to access a website on the internet), it can ask public DNS servers on the internet, if they have the answer they will tell the local DNS, which will tell you. If they don't, they will ask another public DNS server and continue the chain until resolution.

This local DNS infrastructure not only simplifies the way devices communicate within the network but also provides a layer of control and security. Network administrators can customize DNS settings, block access to certain websites, and ensure efficient resource allocation.

In essence, whether you're navigating the vast expanse of the internet or your local network, DNS serves as the backbone, seamlessly translating domain names into IP addresses and facilitating smooth communication between devices.