Suggest an editImprove this articleRefine the answer for “What is DNS?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**DNS (Domain Name System)** is a **system and protocol** that **translate domain names into IP addresses**. In simpler terms, DNS is the "phone book of the internet". **Key point:** DNS does not load the website itself - it only tells you where to go.Shown above the full answer for quick recall.Answer (EN)Image**DNS (Domain Name System)** is a **system and protocol** that **translate domain names into IP addresses**. In simpler terms: **DNS is the "phone book of the internet"**. --- ## Why DNS is needed Computers on a network **do not understand website names**, they only work with IP addresses, for example: ``` 142.250.184.206 ``` Such addresses are inconvenient for people to remember, so we use names instead: - `google.com` - `github.com` - `example.com` **DNS links a website's name to its IP address**. --- ## How DNS works (very simply) When you type a website address into your browser: 1. The browser asks: **"What is the IP address of example.com?"** 2. The DNS server looks for the answer 3. The DNS server returns the IP address 4. The browser connects to the server **using that IP** DNS **does not load the website** - it only tells you *where* to go. --- ## Why DNS belongs to networking and the internet DNS: - runs automatically every time a site is opened - is used by browsers, applications, servers - is the **foundation of how the internet works** Without DNS: - IP addresses would have to be entered manually - the internet would be extremely inconvenient --- ## DNS hierarchy (briefly) DNS is a distributed system: - root DNS servers - domain zone servers (`.com`, `.ua`, `.org`) - DNS servers for specific domains Thanks to this, DNS is: - scalable - fast - has no single point of failure --- ## What matters for an interview - DNS is **not a single server**, but a system of servers - DNS works on a **request -> response** basis - DNS mostly uses **UDP**, but sometimes **TCP** - DNS does not transfer pages or files --- ## Real-life example DNS is like contacts in a phone: - you pick a name - the phone substitutes the number - then you call using that numberFor the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.