An IP address is a unique number (e.g. 18.104.22.168) assigned to a computer (or other internet-capable information appliance, such as a network printer) to enable it to communicate with other devices using the Internet Protocol. It is a computer’s identity on the internet, and every computer connected to the internet is assigned at least one — although the methods of assigning these addresses, and the permanence and duration of their assignment, differ according to the use of the computer and the circumstances of its internet use.
Every web server is assigned an IP address as well, but often times hosting providers will assign multiple IP addresses to one computer, in the event that multiple web sites reside on the same physical server. This is the case with most inexpensive ‘managed’ or ‘group’ hosting packages.
Domain names were created to provide an easier means of accessing internet resources than IP addresses, which are cumbersome to type and difficult to remember. Every domain name has at least one corresponding IP address, but only a small number of IP addresses have a domain name associated with them, since only computers that are servers require domain names. The domain name system (DNS) is what maps domain names to IP addresses.