What is a Subdomain?

A subdomain is a subdivision of a domain name. The most common subdomain on the internet is www (i.e. www.kevinmuldoon.com); however many website owners use subdomains for different areas of a website.

For example, a website owner could use blog.website.com for their blog, forums.website.com for their forums, shop.website.com for their online store, and support.website.com for their help department.

Subdomain Term Confusion

A subdomain is not to be confused with the terms “Addon Domain” or “Parked Domain”.

An addon domain is used by many hosting companies to refer to the option of hosting additional websites under one account. When the term addon domain is used, additional websites are typically stored in unique folders. For example, if kevinmuldoon.com was setup as an addon domain, it may be stored in a directory entitled kevinmuldoon.

A parked domain refers to a domain name that is not being used. The parking domain may display a temporary landing page or it may be used to redirect the user to another domain.

Subdomain vs Subdirectory

One of the decisions many website owners face is whether to place key areas of their website in subdomains or in subdirectories. For example, do they want to place their blog at blog.website.com or www.website.com/blog.

From a maintenance point of view, there are benefits to placing certain areas of your website in subdomains as it allows you to host each area using a different setup. You could, for example, optimise a server specifically for hosting your online community at forums.website.com and then use a dedicated WordPress host

I have always kept everything hosted under one hosting account and put all areas of my websites into subdirectories; however I know of many websites who frequently use subdomains.

One important thing you need to keep in mind when making this decision is that from an SEO perspective, each subdomain is treated as a separate entity by search engines.

Because of this, most SEO experts recommend keeping vital sections of your website such as blogs at www.website.com/blog/ instead of blog.website.com.

If you have an international audience, subdomains are useful as you can place local websites in their own subdomain and market them effectively in each region. Such as en.website.com for English, fr.website.com for French, and es.website.com for Spanish etc.

Reserved Subdomains

A number of subdomains are created when a server is setup. For example, servers that use cPanel/WHM typically reserve mail, www, ftp, cpanel, whm, webmail, and webdisk.

You are not permitted to create a subdomain using a name that is already reserved by your hosting company.

Please check with your website hosting company if you are unsure about which names are reserved for subdomains.

Configuring a Subdomain

There are two ways of configuring a domain name. You can either configure a subdomain via your domain registrar or via your website hosting space.

Configuring a subdomain through your domain registrar gives you complete control over how the subdomain is managed. You can, for example, host each subdomain on a different server.

The process of setting up a subdomain is slightly different for each domain registration company. Some may require you to create a DNS record while others adopt a more user-friendly approach and provide customers with an option to create subdomains directly.

Below you will find articles from some domain registrars that explain how a subdomain is created through their domain control panel. Be sure to speak to your domain registrar directly if there is no equivalent article available from your domain registration company or if the process of creating a subdomain is not clear.

Configuring your subdomain through your web hosting control panels is (normally) much simpler.

Take cPanel, for example.

All you have to do is log in to your website hosting control panel.

cPanel Home
The cPanel home screen.
cPanel Subdomains
cPanel Subdomains

Below you will find some guides to setting up a subdomain in some popular control panels. Speak to your hosting company if you are unsure about any aspect of this.

WWW vs Non-WWW

There are thousands of articles online explaining the benefits of using www or non-www with your website. Most articles focus on why it is better from a user's point of view and why it is better from an SEO point of view.

The truth is that there are absolutely no SEO benefits of selecting one form over the other. Search engines such as Google allow you to select your preferred domain and do not recommend any particular format.

Despite this, you will find many people online stressing the importance of using www or stressing why you should not use it. Websites such as No-WWW.org recommend not using it and websites such as Yes-WWW.org recommend that you do.

My own preference has always been to use www on my websites because high traffic websites such as Amazon use this format, though there are many other high traffic websites that do not use www so this point is mute.

My recommendation is to choose one format and stick to it as there is no benefits of using one over the other.