Domain Names, URI’s and IP Addresses

What are URL’s, URN’s and URI’s?

  • URL-Universal Resource Locator

A universal resource locator is used to provide the location of a resource on the internet. It is important to know that any URL is considered a URI.

  • URN-Universal Resource Name

A universal resource name provides the name of the resource in question, allthough it does not provide any details about locating the resource.

  • URI-Universal Resource Identifier

The universal resource identifier can be either a URL, URN or it can be a combination of both.

An example of a URL (URI) is: https:// www

  • https:// Is the protocol
  • www. Is the hostname (Domain Name)
  • watch?v=2sb0Mr9wA-U Is the location of the file on the server (Pathname)

It may also be important to note that the www in a website is known as a subdomain.

What is a Domain Name?

A domain name is a part of a URL which is used to identify an IP address, this can be seen above in the example of a URL. A domain name also gives the user information, this is done through the top level domain (TLD).

An example of a domain name is The top level domain is the .com and the second level domain is the youtube. This is a commercial organisation called bbc This is an organisation, called wikipedia, requesting the english language. This is a governmental organisation in the united kingdom.

What is an IP Address?

It is important to know that an IP address also has a structure, like the URL and domain name. An IP address is split into 4 bytes (1 byte = 8 bits), meaning a IP address is 32 bits long.

00000000.00000000.00000000.00000000 – 11111111.11111111.11111111.11111111 (Binary) – (base 10)

An IP address is also split into two parts, a network and host identifier. The first two bytes is the network identifier and the second two is the host identifier.

Internet Registrars and Registries

Internet Registrars – These allow organisations and individuals to buy their own domain names.

Internet Registries – These hold domain names which are registered. They allow owners to link domain names to IP addresses.

Some domains are linked to multiple IP addresses, this is because the website may have users from all around the world. Having multiple addresses around the world allows the company to route them to the closest IP, giving them a faster and more stable connection. This also allows big sites to manage traffic through load balacing.

How Does a Domain Name become an IP?

This information can be found in a blog post I have already created here!

Websites that go into more detail into the subjects above.

URN, URL and URI’s.

Domain Names.


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