Domain
Name System and Name Servers
While it is possible for Internet clients
to access a server by using its IP address,
it becomes a burden remembering a string of
numbers for each of your favorite sites. This
invites the usefulness of the Domain Name
System (DNS), which broadcasts more “friendly”
names that correspond to IP addresses on the
Internet. With DNS, anyone can type in a domain
name (e.g. mydomain.com) which then gets resolved
(translated) to a numerical address (e.g.
207.159.130.233). As an example, you can see
that in most web browsers you are able to
watch as a domain name is being resolved.
This occurs at the bottom of the browser window.
When you type in a web address the status
bar of your browser may say:
Connecting to site 207.159.153.130...
Web site found, waiting for reply...
This indicates that your
machine was able to match the IP address
to the domain name you entered. In order
to do this, your computer needs to have
some sort of reference in which to look
up domain names and match them to their
corresponding IP addresses, much like how
you would use a telephone book to correspond
a friend’s name to their number. DNS,
commonly referred to as your Name Server,
is the computer’s phone book for the
Internet.
When you initially set up
your computer to connect to the Internet
you were required to give it at least one
name server so it would know where to look
up the IP addresses of the domain names
you access. Most people use two name servers:
primary and secondary. This provides a redundant
system so that in case one fails there is
a backup. In the above example, you could
have simply typed in the IP address of the
server and the connection would have been
made without needing to consult a name server.
However, most people on the Internet, without
knowing it, rely heavily upon DNS, so that
they don’t have to worry about keeping
track of all those IP addresses.
A name server’s only
function is to maintain a table of domain
names and matching IP addresses, called
a DNS Table. Each domain name on the Internet
has specific DNS servers that are responsible
for keeping their information in their table
and that DNS server is then responsible
for broadcasting that information across
the Internet.
Most likely, you chose a
domain name for your account when you first
signed up. Even if you didn’t choose one,
often we can assign you a temporary IP. In either
case, your domain already has an entry in
the DNS tables of our name servers. This
entry is an important part of what makes
it possible for people to access your site
on the Internet.
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