Dynamic host configuration protocol, an update/extension of the boot protocol (or BOOTP), is a protocol used to assign dynamic IP addresses to machines (like my computer) on a network.  When a device is connected to a network—either your corporate network or, very likely, your ISP—it requests and receives a dynamic IP address from the network’s pool of available addresses.  The beauty of DHCP is that it allows addresses to be assigned automatically, rather than by an administrator.  Imagine how inconvenient it would be to have to wait for some surly administrator to type in your dotted octal code before you could check your email!     

“But wait,” you are thinking, “when I log into my bank’s website, I don’t type a bunch of numbers.  I type www.MyBanksName.com.”  The reality is, the bank’s website truly is at 161.150.129.166.  But numbers are hard to remember, so part of the Internet magic is a bunch of computers which map website names to numbers, like www.MyBanksName.com =  161.150.129.166 or  www.HappyAbout.com = 208.97.156.56. Get ready for another TLA… these name-mapping computers are referred to as the domain name service (DNS) servers.  When I type the name—technically known as a URL, which stands for uniform resource locator—one of these computers springs into action, translates the name into numbers, and places the call to that numerical address.

You can determine the IP address of a website using a utility called nslookup.  In order to use this application, open a DOS prompt, if you’re old.  Younger Windows users won’t know what this means, so just click on the “Start” button, click on “Run…” and type cmd in the box. (If you are running Vista, my condolences . . . just type cmd in the search box to get to a command prompt)  Anyway, no matter how you do it, once you get a boring looking black screen, just  type nslookup example.com where “example.com” is the website name you want translated into numbers.  (I know some of you are still out there typing nslookup example.com, but I did everything I could to stop you.)  You will see the name of the URL that you typed in, or some of you will see “example.com,” followed by the IP address of that URL.  Had enough?  Type exit to leave this strange world where only words are used and mouse clicks are ignored. 

Next time up: finding your IP address