Domain name facts for kids

An annotated example of a domain name

On the Internet, a domain name is a special text address that helps people find websites and other online services. Think of it like a street address for a house, but for a place on the internet. Domain names make it much easier to remember where to go online than using long numbers. They are used for things like websites, email services, and many other online activities. Each domain name points to a specific location on the internet, like a computer server.

Domain names follow specific rules set by the Domain Name System (DNS). Any name registered in the DNS is a domain name. These names are organized in levels, starting from a main "root" that has no name. The first level includes top-level domains (TLDs), such as popular ones like com, info, net, edu, and org. There are also TLDs for different countries, like .uk for the United Kingdom. Below these, you find second-level and third-level domain names, which are what people usually register for their websites, like "wikipedia.org". You can usually register a domain name through a company called a domain name registrar.

A fully qualified domain name (FQDN) is a complete domain name that shows all its parts in the right order. For example, "www.example.com." (with a dot at the end) is a fully qualified domain name. Domain names don't care about capital letters, so "example.com" is the same as "Example.com". However, they are usually written in lowercase. A hostname is a domain name that has at least one IP address connected to it, meaning it points to an actual computer or server.

Understanding Domain Names

Why We Use Domain Names

Domain names help us identify internet resources like computers, networks, and services. They give these resources easy-to-remember text labels instead of complicated numerical addresses. A domain name can represent a whole group of resources or just one specific item. For example, a domain name can be the address for a website like "en.wikipedia.org".

Domain names also act as simple labels to show who owns or controls an online resource. This is important for things like verifying emails or identifying different online services. A key job of domain names is to give us names that are easy to recognize and remember for internet resources that actually use numbers. This clever system lets a website or service move to a different physical location on the network without changing its easy-to-remember domain name.

Organizations often choose domain names that match their own names. This helps internet users find them easily. Some domain names are very general, like "books.com" or "music.com". These can be very valuable because they describe a whole category, not just one company. People sometimes call domain names "domains" and those who register them "domain owners." However, registering a domain name only gives you the exclusive right to use it for a certain time, not full ownership.

A Quick Look at Domain History

The idea of using simple names instead of numbers for computers on a network started a long time ago, even before the modern internet. In the early days, a central computer kept a list of all computer names and their numerical addresses. But as the network grew very fast, this system became too hard to manage. So, in 1983, the Domain Name System (DNS) was created to organize these names better.

Here are some of the very first domain names registered:

And the first five .edu domains, all registered on the same day:

How Domain Names Are Built

The hierarchical domain name system, organized into zones, each served by domain name servers

Today, a group called the Internet Corporation for Assigned Names and Numbers (ICANN) helps manage how internet domain names are set up. They approve companies called domain name registrars, who are the ones that let you register and use domain names.

A domain name is like a tree structure, with different levels. Each part of the name, separated by dots, is called a "label." For example, in "www.example.com":

• The label on the far right, "com", is the top-level domain.
• The labels go from right to left in order of importance. Each label to the left is a smaller part, or subdomain, of the one to its right. So, "example" is a subdomain of "com", and "www" is a subdomain of "example.com".
• Each label can be between 1 and 63 characters long. The entire domain name can't be longer than 253 characters.
• A hostname is a domain name that has an IP address linked to it. For instance, "www.example.com" is a hostname, but "com" by itself is not.

Top-Level Domains (TLDs)

When the Domain Name System was first created, domain names were split into two main groups. The country code top-level domains (ccTLDs) used two-letter codes for countries, like ".us" for the United States. There were also seven generic top-level domains (gTLDs) for different types of organizations, such as gov (for government), edu (for education), com (for commercial), mil (for military), org (for organizations), net (for networks), and int (for international organizations). These TLDs are the highest level of domain names on the internet. Every domain name ends with a top-level domain.

As the internet grew, more generic top-level domains were added. By 2016, over 1000 gTLDs were active. The Internet Assigned Numbers Authority (IANA) keeps a list of all top-level domains. IANA also sets aside special domain names for testing or examples, like example and test. Some companies even have their own brand names as TLDs, like .google or .bmw.

Second and Lower Level Domains

Below the top-level domains are the second-level domain (SLD) names. These are the names directly to the left of TLDs like .com or .net. For example, in "example.co.uk", "co" is the second-level domain.

Then come third-level domains, which are to the left of second-level domains. There can be even more levels, like fourth or fifth, with almost no limit. Each level is separated by a dot. For example, "sos.state.oh.us" has four levels of labels. In general, subdomains are domains that are part of a larger parent domain.

Second-level or lower-level domain names are often chosen to match a company's name (like "bbc.co.uk") or a product (like "hotmail.com"). Further down, labels might point to specific servers, like "ftp.example.com" for an FTP server or "www.example.com" for a website server. Today, one server can host many websites, and one website can use many servers to handle lots of visitors.

Internationalized Domain Names

The original Domain Name System only allowed certain English letters, numbers, and hyphens. This made it hard for people using other languages to have domain names in their own scripts. To fix this, the Internationalized domain name (IDNA) system was created. It lets people use characters from different languages, like those with accents or different alphabets. These names are then converted into a special code that the DNS can understand. For example, a name like "københavn.eu" might be converted to "xn--kbenhavn-54a.eu" behind the scenes.

Getting Your Own Domain Name

Who Manages Domain Names?

The right to use a domain name is given out by domain name registrars. These registrars are approved by ICANN, the organization that oversees the internet's naming and numbering systems. Each top-level domain (like .com or .org) also has a registry, which is like a big database that keeps track of all the names registered under that TLD. The registry gets information from registrars and makes it available using special tools like WHOIS.

Registries and registrars usually charge a yearly fee to let you use a domain name. People often say they "buy" or "own" a domain name, but it's more accurate to say they have the exclusive right to use it for a specific period. The people who register domain names are called "registrants" or "domain holders."

ICANN publishes lists of all TLD registries and domain name registrars. Information about who registered a domain name is kept in an online database that you can look up using the WHOIS tool.

How to Register a Domain

When you register a domain name, you usually provide a few important pieces of information:

• Administrative contact: This person manages the domain name and has the most control over it. They handle things like the official name, address, and contact details for the domain holder.
• Technical contact: This person manages the domain's name servers. They make sure the domain works correctly and is always accessible.
• Billing contact: This person is responsible for paying the fees to the domain name registrar.
• Name servers: These are special computers that help connect your domain name to your website. Most registrars offer name servers as part of their service, or you can use your own. You usually need at least two name servers.

Domain names are made up of labels that can include letters (a-z), numbers (0-9), and hyphens (-). They cannot start or end with a hyphen. Capital letters don't matter in domain names.

The Value of a Domain Name

Domain names are often compared to real estate. Just like a good location for a house, a good domain name can be very valuable. This is because it's the foundation for a website and can help with branding, advertising, and how easily people find it online.

Some companies offer very cheap or even free domain registrations. They usually do this by hosting your domain on their website, often with ads, and they make money from those ads to cover their costs. If you own a domain, you can also create many subdomains under it, like "blog.example.org" or "shop.example.org".

Many popular domain names are already taken. So, people often use online tools to search for available names or get suggestions for similar names.

Important Things to Know About Domains

Reselling Domain Names

There's a business called the domain aftermarket where people buy and sell registered domain names. The value of a domain name can depend on many things, like how easy it is to remember, how popular the words are, or its potential for a business. The most expensive domain sales often happen privately.

Avoiding Domain Name Mix-ups

Sometimes, domain names can be confusing if they are read incorrectly. Even though domain names don't care about capital letters, how they are written can change how people understand them. For example, a website called "Experts Exchange" used to be "expertsexchange.com". They changed it to "experts-exchange.com" to make it clearer and avoid misinterpretations. Adding hyphens can help prevent these kinds of mix-ups.

What Are Fictitious Domain Names?

A fictitious domain name is a domain name used in stories, movies, or TV shows that doesn't actually exist. It's like how movies use the fake phone number "555". The official fictitious domain name for examples is "example.com", and there's even a TLD called ".example" for this purpose.

Sometimes, people register these fictitious domain names in real life, either by the creators of the story or by others hoping to make money from them. For instance, after a TV host joked about "Hornymanatee.com", the TV network bought the domain and created a website for it!

Staying Safe from Tricky Domain Names

Some people try to trick internet users with domain names that look real but are not. This is called domain name spoofing, and it's a type of phishing attack. The goal is to make you visit a fake website or open a fake email.

What is Typosquatting?

Typosquatting (also called "URL hijacking" or "fake URL") happens when someone registers a domain name that is a common misspelling of a popular website. If you accidentally type in the wrong address, you might end up on their fake site. These fake sites might try to steal your information or install harmful software.

Typosquatters often use names that are:

• A common misspelling of the real site.
• A typo you might make by mistake.
• A plural version of a singular domain name.
• Using a different top-level domain (like .net instead of .com).
• Using a similar country code TLD (like .co instead of .com).

What is an IDN Homograph Attack?

An IDN homograph attack uses domain names that look very similar to real ones but use characters from different alphabets. For example, the letter "A" looks the same in the Latin, Cyrillic, and Greek alphabets, but they are different characters to a computer. So, a fake website might use a Cyrillic "A" to make its domain name look exactly like a real one. Many web browsers will warn you about these "mixed alphabet" domain names, but not all applications do.

Protecting Yourself Online

To avoid these tricks, always be careful when typing domain names. Double-check the address before clicking on links or entering personal information. If something looks suspicious, it's best to avoid it. Companies that own popular domain names often register common misspellings to protect their users. Technologies like SSL certificates (which show a padlock in your browser) help ensure that a website is legitimate and secure.

See also

In Spanish: Dominio de internet para niños