To find a device or service on the Internet you will need to know the address of that device/service.
There are two internet addresses that most of you will no doubt already have encountered, they are the:
- Website address known also as the website url (uniform resource locator). These are the addresses you type into your web browser- e.g. http://www.steves-internet-guide.com
- Email address e.g. firstname.lastname@example.org
One thing you should notice straight away is how similar they are.
To emphasis this I’ve highlighted the common component.
The component that I’ve highlighted is the domain name.
The domain name is the Internet equivalent of the telephone number, or for standard mail the postal address.
The domain name is the fundamental building block of the web, and makes the many Internet services like email, websites, instant messaging etc possible.
Website Addresses (Website URLs)
The website address is also known as the URL (uniform resource locator) or URI (uniform resource indicator) and is used to locate a web page/document or more generally a resource on the web.
The term URL is used when the resource is a web page, and the term URI when the resource is a service ,API endpoint etc.
A URL consists of three distinct parts as shown in the schematic below:
- Protocol: normally http (hypertext transfer protocol)
- website: e.g www.steves-internet-guide.com
- Web page name e.g understanding-web-addresses
So http://www.steves-internet-guide.com/understanding-web-addresses is the address of this page.
You should notice a few things about the URL:
- Forward slashes are used to separate various parts of the URL.
- dots are used to separate parts of the domain name.
- www (stands for world wide web) is a convention and not strictly speaking necessary as the site can be accessed using:
http://steves-internet-guide.com/ without the www
- You don’t need to type the entire URL into the browser address bar. I almost never type in the protocol but use just www.steves-internet-guide.com instead. Modern browsers insert the protocol for you.
The email address consists of two parts:
- Mailbox name
- Domain name
the two parts are separated by the @ sign e.g.
no-reply is the mailbox name and steves-internet-guide.com is
the domain name.
Most newcomers to the Internet use the email services of free providers like Google and have addresses like:
in this case the domain name is owned by Google, and in order to use the service you need to create a mailbox name (in this case Jsmith123).
Because there are many people with the name John, and so you usually end up with a mailbox name like Jsmith123 or something equally obscure.
The domain name is the most important part of the web address.
A domain name is used to represent the IP address of a device (usually web server,email server) that us connected to the Internet.
Domain names areused because names are easier for people to remember than IP addresses.
Because of the large number of domain names that are in existence they are organised in a hierarchical structure, with fixed and internationally assigned TLDs (top Level domain names).
The most common TLD is the dot com TLD.
Note: Domain names aren’t case sensitive
This organisation is known as the DNS (domain name system). See Beginners Guide to DNS
Resources and references:
- An Introduction to the HTTP Protocol for beginners.
- Basic Networking Course for Beginners
- Understanding the domain name structure