Anatomy of a URL
by Andy Wibbels
http://andywibbels.com/

A web address has many parts.

Understanding which parts do what can
help you better understand how your
readers and search engines see your site.

www.yourdomain.com
Here’s a domain name.

www.yourdomain.com
Let’s break it down into its many
parts.

www.yourdomain.com
That thing on the end? That’s called a
Top Level Domain.

Common top-level domains
.com .net .org
• For • For internet • For non-
commercial service profits
entities providers
.edu .mil .gov
• For • For military • For US
educational use gov’t
institutions bodies

Each country has it’s
own top-level domain:
.uk .ch .ph .th
.us .tv .ca .au
.cc .sp .fr and so on…
Full list at http://en.wikipedia.org/wiki/Country-code_top-level_domain

www.yourdomain.com
So that’s the top-level domain, the
part after the ‘dot’ and before the
‘everything else.’

www.yourdomain.com
Let’s take a look at the part
‘between the dots.’

www.yourdomain.com
It doesn’t allow spaces or
underscores.

www.yourdomain.com
www.YourDomain.com
www.YOURDOMAIN.com
It is not-case sensitive.
All of the above go to the same
place.

www.your-domain.com
You can have dashes.

www.yourdomain12.com
Or numbers.

www.yourdomain12.com
Together with the top-level domain.
This is what most people mean when
they talk about ‘a domain name.’

www.your-domain12.com
www.your-domain12.net
www.your-domain12.org
www.your-domain12.au
These are all different domain
names, that might be owned by
different people.

www.your-domain.com
So that was the part ‘between the
dots.’

www.your-domain.com
Let’s look at the part ‘before the dot.’

www.yourdomain.com
The part before the first dot is called
the sub-domain.

www.yourdomain.com
Yes, you’re right. It doesn’t make
sense that it is ‘sub’ and is first as you
read it out loud.

www.yourdomain.com
Make peace with that.

www.yourdomain.com
mail.yourdomain.com
blog.yourdomain.com
stuff.yourdomain.com
Sub-domains allow you to channel
different bits of traffic to different
parts of your company.

www.yourdomain.com
mail.yourdomain.com
blog.yourdomain.com
stuff.yourdomain.com
All of these sub-domains are
controlled by the same person that
owns the domain name.

www.yourdomain.com
The default is ‘www’
for ‘world wide web.’

www.mail.yourdomain.com
A common mistake is adding the
‘www’ if there is already a domain
name.

www.mail.yourdomain.com
That isn’t necessary and may cause
weird error messages.

yourdomain.com
=
www.yourdomain.com
Depending on how a site is setup,
you don’t have to type in the ‘www.’

yourdomain.com
≠
www.yourdomain.com
Other times they are different.
This small detail may drive you batty
when troubleshooting so be vigilant.

www.yourdomain.com
So: sub-domain.

www.yourdomain.com
Domain.

www.yourdomain.com
Top-level domain.

www.yourdomain.com
Usually referred to as one big thing
called ‘a domain name.’

http://www.yourdomain.com
So what’s this H-T-T-P business?

http://www.yourdomain.com
There are many ways for you to
connect to a website.

http://
The most common used by browser is
Hypertext
Transfer
Protocol

http://
Hypertext is a nerdy way of saying
‘web site stuff.’

http://
The http:// tells the web server how
to respond to the request to view a
particular web page or file.

http://
The colon and 2 forward slashes just
make it look fancy.

http://
Yes, the direction of the slashes matters.
If they lean to the right – into the direction
you’re reading, they are forward slashes.
If they lean to the left – they are backslashes.

http://www.yourdomain.com
Another piece of the puzzle!

http://www.yourdomain.com/stuff
Uh-oh. What’s this?

http://www.yourdomain.com/stuff
This tells the website, I want to see
your folder of stuff.

http://www.yourdomain.com/stu_ff
http://www.yourdomain.com/1 23
http://www.yourdomain.com/FuN
This folder on the webserver can be
case sensitive and can contain spaces
and underscores. It is separate from the
domain name system.

http://www.yourdomain.com/stuff
This part points us to the server. This part tells
us what to get
once we’re
there.

The path to these files can be as long
as it needs to be.
http://www.yourdomain.com/stuff/something/important.pdf
This part points us to the server. This part tells
us what to get
once we’re
there.

http://www.yourdomain.com/stuff.xls
This tells the website, I want to see a
spreadsheet called stuff.xls.

http://www.yourdomain.com/stuff.htm
This tells the website, I want to see a
webpage called stuff.htm.

http://www.yourdomain.com/stuff
If there is no file requested – just the
folder – the server may respond with
the ‘index’ of that folder.

Sometimes a URL has variables in it
that tell the site what to do. Here is
the full URL to my Facebook profile.
http://www.facebook.com/profile.php?id=505504719
The browser talks to Facebook and asks for the the profile.php file is a
profile.php file script and looks for a
variable called ‘id’ and that
is how it knows what
Facebook profile to show.

But at the end of the day, the
important thing to remember is this:

www.yourdomain.com
Sub-domain.

www.yourdomain.com
Domain.

www.yourdomain.com
Top-level domain.

www.yourdomain.com
Usually referred to as one big thing
called ‘a domain name.’

Thanks!
Let’s connect:
http://andywibbels.com/