What is IP (internet protocol)

Every device connected to the public Internet is
assigned a unique number known as an Internet
Protocol (IP) address. IP addresses consist of four
numbers separated by periods (also called a
'dotted-quad') and look something like 127.0.0.1.
Since these numbers are usually assigned to
internet service providers within region-based
blocks, an IP address can often be used to identify
the region or country from which a computer is
connecting to the Internet. An IP address can
sometimes be used to show the user's general
location.
Because the numbers may be tedious to deal with,
an IP address may also be assigned to a Host name,
which is sometimes easier to remember. Hostnames
may be looked up to find IP addresses, and vice-
versa. At one time ISPs issued one IP address to
each user. These are called static IP addresses.
Because there is a limited number of IP addresses
and with increased usage of the internet ISPs now
issue IP addresses in a dynamic fashion out of a
pool of IP addresses (Using DHCP). These are
referred to as dynamic IP addresses. This also
limits the ability of the user to host websites, mail
servers, ftp servers, etc. In addition to users
connecting to the internet, with virtual hosting, a
single machine can act like multiple machines (with
multiple domain names and IP addresses).