When you click a link,
you probably don't think much about how the page that appears actually got
in front of your eyeballs.Do you?
I never did, until I started my own web hosting business. Then I
*really* started to care. Let's look at *why* your web site is
displayed when someone clicks a link.
And just as importantly, let's see why pages sometimes *don't* get
displayed when requested!
It's all about something called "the DNS". DNS stands for Domain Name
System. Don't be fooled, the DNS is actually software that does a job so
vital the Internet would cease without it.
DNS lets people locate computers on a network using words instead of
numbers. Computers obviously work only in numbers as everything has to be
translated into numbers at some point. But we humans don't do so well
remembering a bunch of meaningless digits.
When you register a domain name, you have to "point" it to a computer
called a "Name Server". There's an IP number or IP address associated with a
domain name.
The DNS server maintains a database of domain names and their
corresponding IP addresses. In this hypothetical example, if www.mycompany.com
were presented to a DNS server, the IP address 204.0.8.51 would be returned.
And the page created by some human would be displayed.
In a real example, if you were to simply type "
"
into the address bar, it does a little trick called "resolving" which means
the name is turned into the site's IP number. Thus, "taghosting.net" is
*really* "64.239.15.99"... and the DNS works the magic behind the scenes.
(NOTE from Linda: Tag Hosting no longer exists, so you will
have to try a different IP address.)
The above is a simplification of a complex process. But now you may
better understand *why* it is so important to "update the DNS" when you move
to a new web hosting company. Your old host used a totally different Name
Server... and your old site had a totally different IP address. When you
update the DNS, you're "pointing" the domain to the new Name Server, and to
the subsequent IP address for you site.
Ever read or heard the term, "reverse DNS"? That's simply where an IP
number is used to locate a domain name. It performs the opposite function of
the DNS, which turns names into numbers.
Turning names into numbers is the job of the DNS.
Turning numbers into names is the job of the Reverse DNS. Turning numbers
into dollars is the job of people. Ah, but that's another topic entirely!
Reverse DNS is used by Internet Service Providers to monitor traffic, log
statistics, and make sure that email is actually coming from the same domain
in the FROM field.
Recap: You register a domain name. You associate a Name Server
with that registration. The domain name you registered "points" to the name
server, and whenever anyone types in your URL or clicks a link with your
domain in it, they're sent to your site. Without that DNS "pointer"...
they'd never get there. When you change hosting companies, you have to
update the DNS, or, in other terms, "modify the DNS". You simply log into
your Registrar's database, find the link that lets you update the DNS, and
type in the new name server information. This info is always supplied by the
new web hosting company.
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