Why 80: a primer on ports

I absolutely adore my license plate, and I consider myself very lucky to have gotten it. As far as personalized plates for standard web protocols goes, this is probably the best plate there is (it’s way better than HTTP 1 through 79, or 81 and above, to be sure). A lot of non-geeks ask me why I chose 80. Here’s why.

When a computer tries to connect to a server over the Internet, one of the first things it tells the server is which port number it is trying to connect to. The port number can be anything from 0 to 65535, and it’s used to determine which program should be run to handle the connection. Most HTTP servers are triggered on port 80, which is why I chose HTTP 80 for my license plates.

If you’d like, you can try changing the port number yourself. In your address bar, try adding :80 after the domain name and before the path (so, michaelcgorman.net:80/2011/…). You should still see the webpage. (Since 80 is the standard port number that is assumed when you don’t specify otherwise, some browsers will remove the :80 from the URL.) What happens when you try another port, like 22? Chances are, it doesn’t work. If you have a “smart” browser, it may even try redirecting you to the same page over port 80.