Internet Basics - the IP Address

Eventually I'll add some posts on the history and beginning of the Internet but for now, I'm going to focus on the technical components of the Internet.  We will start with IP addresses.  What is an IP address?

If you think about a street address, it is a way to provide information to allow others to find you.  Here is an example from the US Post Office web site.

Name or attention line:	JANE L MILLER
Company:	MILLER ASSOCIATES
Delivery address:	1960 W CHELSEA AVE STE 2006
City, state, ZIP Code:	ALLENTOWN PA 18104

In the same manner, an IP address provides a way for computers to find each other to communicate.  We'll talk about different versions of IP addresses but for now, we'll focus on the original version called IPv4.  An IPv4 address is represented with 4 different decimal numbers in the range between 0-255 which are separated by dots.

Sample IP address: 74.125.224.72

These IP addresses are used by routers* on the Internet to direct traffic to the right computer and websites.  Every computer and web site on the Internet can be reached by an IP address.  In fact, if you go to the web browser and type the sample IP address above, that will reach the Google web site (at least as of the time of this article).

Now you have a high level understanding of how computers can communicate and find each other.  As a human though, to memorize the address of all the websites on the Internet would be enormously challenging if you had to do it by IP address.  In the next post, we'll talk about how the problem was addressed using the Domain Name System or DNS.


 * Routers are specialized devices that send data between networks.  For example, they make sure requests you make from your browser are sent to Google's web site to do a web search.  We'll provide later articles with more details.