WebAdmin 101-A4 – Sub-Domains

4. Sub Domains

What is a sub-domain, and what can it do for your web site? A sub-domain is exactly what it sounds like: a sub directory or sub domain of your original domain.

Sub domains usually look something like this - store.bookshop.com.

Note how the original domain is probably www.bookshop.com. The “store” that is placed in front of the original domain name re-addresses that domain into a sub domain.   The name of the sub-domain becomes the three-part name, store.bookshop.com not just “store“.

If you remember back to lesson 101-A2, I introduced you to the concept that the “www” is actually the server name and not part of the domain name.  The same philosophy applies to sub-domains. 

Thus in our example, “store.” could be a server name, even though it is being used as a sub-domain name,  or, it might simply be a storage area on a hard drive that holds a sub-website with unique appearance and properties, compared to the parent site. 

That hard drive might be in a different computer to the parent site, and establishing it as a sub-domain allows easier connection between the two, and a more logical addressing system.  Remember the “house number ~ street name ~ street type” analogy I used in WebAdmin 101-A2?  well, with subdomains, you could think of it as “house number ~ apartment number ~ street name ~ street type“.  The server “www” is the house number, the sub domain “store” is the apartment number, and so on as before.

Consider this illustration, modified from one in the Exchange Server 2000 Help files written by Microsoft (they have discontinued support for Exchange Server 2000 and Windows 2000, so I hope they have no problem with sharing “redundant” images?).

The note I’ve added to the diagram shows a possible, but unusual addressing for cascading sub-domains.

It would be more normal to move the “www” to the front of the URL, however, in theory, there is nothing to stop it from being in its normal place immediately before the main domain name, and after server names that don’t follow the usual naming conventions of “ftp“, “www“, etc.  It is however, very likely that using server-type’s names for sub-domains would cause problems with public Domain Name Servers (WebAdmin 102D – DNS, will explain this more fully – for now, just consider naming sub-domains with the server-type names, as being a major no-no).  Thus, those sub-domains of the “www” node should be treated as site / directory folders – e.g. www.microsoft.com/public and www.microsoft.com/corporate.

Why Do You Need A Sub Domain / Subdomains?
Sub-domains are usually used simply to organize a web site in a clear and efficient manner – usually to assist the designers, but if done well, it can also help the users too.  Sub-domains can be thought of in the same way as having multiple hard drives in a computer, or the different drawers in a filing cabinet – either example is used to separate information into logical storage areas. 

• Web browsers can read sub-domains easily, and web surfers and customers have become used to the format of sub-domains, even if they didn’t recognise they were using them.  
• Sub-domain names make it easy to organize any web site into sections that are easy to identify and label. 
• Web sub-domains also make it easy for clients and web surfers to get to the web page that they need, without having to go through the main page. 

In other words, your website’s topmost sub-domains make it very easy for web surfers and clients to find just the information they need, right when they want it.  As an example, if you wanted to come (here) to the BuildaSkill Biz Blog, without going through the portal system on the home page of www.buildaskill.com, you could navigate directly to the blog by typing www.buildaskill.com/blog, or, you could go to the discussion boards and forums by typing www.buildaskill.com/board.

Try this experiment – open a new browser window, then copy and paste (don’t click on the links) each of these two addresses -

• www.buildaskill.com/blog
• www.blog.buildaskill.com

What happened?  With the first one, you’ll have gone straight to the home page of the BuildaSkill global Biz Blog, but, with the second one, you’ll have been redirected to a search-engine “page not found” result – yes?  That’s because the blog is run from a sub-folder in the BuildaSkill website, instead of a sub-domain. 

Why?  In all honesty, it’s me being lazy and sloppy.  I forgot to set the subdomains when I first installed the blog software, and have just never got around to it since then.  (Where’s that “innocent whistling” smiley when you need it?).  

But, you can see from this, that when a sub-section of a website is in a sub-folder (as opposed to a sub-domain), you have to use conventional extended URL format for it’s address.  That’s important to remember – you cannot shortcut on sub-domaining, you have to create the sub-domain and point your name servers to it.  You don’t need to do that for a sub-folder, which makes sectioning of websites a lot easier for beginners, even if it makes URLs a little longer sometimes. 

In fact, because a sub-domain is setup in a folder inside your website structure, once you’ve created the sub-domain, if you forget to set the name servers, you and your users cans till navigate to the sub-domain by using normal sub-folder addressing in the URL.

The normal and preferred way to input URLs, (rather than the absolute hierarchal style of www.blog.buildaskill.com and www.board.buildaskill.com) is by using the first style (with the /blog and /board suffixes).  It means you don’t need to know if your target is in a sub-domain, or in an ordinary sub-folder, the suffix name-style will work with, and take you to, either a sub-domain or a sub-folder.

Whether you choose sub-domain ranking, or another kind of organizing principle such as sub-folders, you will probably want to use some kind of sub-domains on your web site if it will have several clear and distinct sections that will contain disparate data or need distinctive visualisation, page layouts, and colours. 

Now here’s the important bit relating to that – sub-folders can inherit colours and page layouts from the top (root) of the website.  Sub-domains cannot (without some “clever” programming).  Each sub-domain will normally have its own unique colour schemes, page-layouts, font styles etc.

Therefore, if you’re going to give different sections of your website their own and unique “identities”, you should be using, either sub-domains, or, different software for each section, each in its own folder.  However if you want a quick and easy way to “cascade” styles down through the whole web, then using sub-folders will ultimately save development time and cost.

What if I want to make a folder into a sub-domain, or a sub-domain into a TLD?

Yes, you can do it, if you do it in the sequence in the question – i.e. promote a folder into becoming a sub-domain, then promote the sub-domain into a TLD.  Making a sub-domain into a TLD is a little trickier than promoting a folder (and the topic of a later article) but essentially means creating a URL redirector. 

Let’s say I’ve promoted the BuildaSkill Biz Blog sub-folder to be a sub-domain called “BlogaSkill“.  If I wanted to make it a TLD, I’d need to register the TLD “blogaskill.com” or “blogaskill.co.uk“, or whatever.

Then, from my webhosting control panel, I’d have to create a redirector to point requests for www.blogaskill.com to point at the blogaskill sub-domain.  Then I’d need to create DNS records on the name servers so that the rest of the world could find the new domain.  More about this later in the series. ….. 

Hmmm – remember the warning I gave a couple of days ago about domain name choosing?  blogaskill = Blog-a-Skill or Blog-As-Kill ?

Finding Website Hosting for Sub-Domains
Not all web host service providers offer sub-domains, although nowadays, most do so.  More commonly, quite a few don’t allow you to set sub-domains yourself, but will do it for you on request.  Almost all of the companies listed in our webhosts list allow you to control your own sub-domaining.  If you are interested in sub-domains and using sub-domain names, you will want to find a web hosting site that allows you to create sub-domains, and which provides strong help and support facilities (if you’re a novice). 

Creating sub-domain web folders is easy if you have a web hosting service that provides the right tools, and allows you (personally) to make sub-domains.  Once created, your web traffic can use them to navigate directly to the desired web pages on your website.

In a few weeks time, in WebAdmin 102, you’ll learn about the different web management tools that webhosts supply as part of their package (or don’t, which is usually the case with UK webhosts), and in the BuildaSkill forums, you can learn, and share queries, about the free, open-source software programs you can install when building websites.  The web management tools normally allow you to create folders within the website you are building, and to designate them as sub-domains. 

Some softwares for local (on your own home PC) web-building, will, when you upload the site to your webhost, create the sub-domain structure for you.  Microsoft FrontPage does this, but only for Windows-based web-hosting, which is becoming increasingly difficult to find, and more expensive when you do so. 

Free Sub-Domain Hosting: Is It A Good Idea?

Perhaps you are interested in a web hosting sub-domain service, that says it can offer you a free sub-domain.  Free sub-domains are certainly a good idea, but be prepared for limited customer service, technical assistance, and other features. If you have a busy web site that receives a high share of traffic, you may want to choose a pay site that can handle the web traffic levels that your web site will get with extra sub domains.  Nowadays, the minimal cost of even “sloppy” TLD hosting still provides better value for money that most of the free sub-domain hosting services, especially if you plan to offer any form of eCommerce functionality.

Finding good sub-domain hosting, that is also free, can be tricky, but free sub-domain hosting is easy to locate if you’re not fussy about support services, and don’t mind the TLD owner splashing adverts and branding all over your pages (adverts you don’t get paid for, but which the webhost might be making a tidy income from).

Tomorrow, I will begin to look at how to register domain names –
If you have any questions about today’s article, please add them to the comments below.

Ed

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