Name server facts for kids

A name server is like a special phone book for the internet. When you type a website address, like `www.example.com`, into your browser, your computer needs to find out where that website lives on the internet. Websites don't actually live at names; they live at special number addresses called IP addresses (like `192.0.2.1`).

A name server's job is to translate the easy-to-remember website name into its numeric IP address. This process is called "resolving" the name. Once your computer has the IP address, it can connect to the correct website server and show you the page. The most famous example of a name server system is the Domain Name System (DNS), which helps the entire internet work smoothly.

What is a Domain Name Server?

The internet uses two main ways to organize information: domain names (like `example.com`) and IP addresses (like `192.0.2.1`). The Domain Name System (DNS) connects these two. DNS servers are special computers all over the world that store and manage these connections.

When you register a new website name, you tell the DNS system which name servers are in charge of your domain. These servers store important information, like the IP address for your website and where your email should go.

The very top of the DNS system is managed by root name servers. These are like the master directories that know where to find the next level of information. Below the root, different organizations manage parts of the internet, making sure that every website name can be found.

Types of Name Servers

Name servers usually work in two main ways: they are either authoritative or recursive. Sometimes, a name server can do both jobs!

Authoritative Name Servers

An authoritative name server is the official source for information about a specific website or domain. Think of it as the main office for a company. If you ask it a question about a domain it's responsible for, it gives you the direct, correct answer. It doesn't need to ask anyone else.

There are two kinds of authoritative servers:

• Primary server: This is the main server where all the original information for a domain is stored. It's like the master copy of the phone book.
• Secondary server: This server keeps an exact copy of the primary server's information. It's like a backup copy. If the primary server goes down, the secondary server can still provide answers, making sure websites stay online. These secondary servers automatically update their copies whenever the primary server's information changes.

Every website name has at least one, and usually more, authoritative name servers. This is for safety, so if one server has a problem, others can take over. When you register a domain name, you provide the names of these authoritative servers.

What is an Authoritative Answer?

When a name server gives an answer that it knows for sure is correct because it's the official source for that information, it marks its answer as "authoritative." This tells your computer that the information is directly from the source, not just something it heard from another server.

Recursive Resolver Name Servers

A recursive resolver (sometimes called a recursive name server) is like a helpful librarian. When your computer asks it for a website's IP address, and it doesn't have the answer immediately, it goes out and finds it for you.

Here's how it works: 1. Your computer asks the recursive resolver for `www.example.com`. 2. If the resolver doesn't know the answer, it starts asking other name servers, beginning with the root servers. 3. It follows the chain of information until it finds the authoritative server for `example.com`. 4. Once it gets the IP address from the authoritative server, it sends that answer back to your computer.

This process is called a recursive query or recursive lookup. It's very helpful because your computer doesn't have to do all the searching itself.

Caching Name Servers

Caching name servers are usually recursive resolvers that also remember the answers they find for a while. This is like a librarian who keeps a list of frequently asked questions and their answers.

When a caching server finds an IP address, it stores it for a certain amount of time. If another computer asks for the same website address soon after, the caching server can give the answer much faster because it already has it saved. This makes the internet faster for everyone and reduces the workload on other name servers.

Many internet service providers (ISPs) offer caching resolvers to their customers. Even your home Wi-Fi router might have a small caching resolver built in to speed up your internet browsing.

See also

In Spanish: Servidor de nombres para niños

• BIND
• Comparison of DNS server software
• Domain Name System Security Extensions
• Lightweight Directory Access Protocol
• Network Information Service
• Name Service Switch (NSS)
• resolver
• Public recursive name servers

External links

• Free and Public DNS Servers
• DNS & BIND Resources