Shared
IP addresses are definately more used that static IP addresses
on the internet.
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The Difference between Static IPs and Shared IPs
One term you see tossed around a lot in web hosting is IP addresses.
There are basically two types of IP addresses: static and shared.
Before the difference between the two is discussed, the definition
of an IP must be discussed.
When someone types in the address: www.yourdomain.com that name
is translated into numbers (called an IP address) and then the
computer is directed to that IP address which is the web site.
Every web site on the internet is found not by its domain name
but by its IP address. IP addresses are in the format similar
to 192.168.0.1, four discreet blocks separated by periods. You
can reach a site by typing in the IP address alone and that will
take you directly to the site. For example www.e3servers.com
resolves (turns into) 64.191.62.74. So if you type in 64.191.62.74
directly into the address bar of your browser you will arrive
the home page of this website.
Now
every single website has an IP address specifically allocated
to it. For example, every single website on this
server does
not use different IP addresses. If every site used a different
IP address there could potentially could be a problem with running
out of IP addresses. (Fortunately this is not a problem and is
going to be resolved when a new IP address standard is fully
adopted). A lot of the sites on this server, and other servers
on the internet, use one IP address for multiple sites. So you
might see joeswebsite.com and marywebsite.com using the same
IP address. Using more than one IP address frees up IP address
which are a limited resource. Basically what happens is that
when joeswebsite.com is resolved into the IP address, the person
looking for joewebsite.com arrives at the server; the server
then realizes that the person is looking for joeswebsite.com
and sends that page to the person requesting it. The server basically
steps in and does a millisecond of work and saves an IP address.
Using more than one site on an IP address is called sharing IPs
or a Shared IP address. If a site has its own IP address, and
shares with no one else, it is called a Static IP address. You
can always reach a site which has a static IP address by using
its IP address alone, but you can’t reach a site using
a shared IP address by typing in the IP address alone because
when you type in a shared IP address you arrive at the server
but the server doesn’t know which site you want because
you haven’t told it which domain name you want. So looking
at our example above, we typed in 64.191.62.74 and arrived at
www.e3servers.com we know that only www.e3servers.com uses this
address because we can get to site without typing in a domain
name and thus it must be a static IP address. But why do you
need a static IP address?
The
main reason for having a static IP address is that you can
only use SSL encryption (the stuff that makes
e-commerce happen)
on a static IP address. In order for a person to transmit sensitive
data over the internet at times this data must be encrypted to
prevent someone from intercepting the information. You can only
use this encryption (called SSL) when the web site has its own
IP address (static IP). It doesn’t work on a shared IP.
So when www.e3servers.com takes in order with a person’s
credit card it needs to encrypt this data and it uses SSL with
its static IP. Another reason for having a static IP address
is that if a web site wanted to have anonymous ftp transfers
(basically where anyone can download files off a site) the site
needs to have a static IP address to handle the anonymous ftp
transfer. Other than these two reasons there is no need for a
site to have its own IP address.
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