How are ports used on a web server?

When two programs on the same computer want to access the internet, they will each use a different port. For example, if you are chatting on AIM and browsing the web at the same time, web traffic will go through port 80 and AIM traffic will go through port 5190. That way when data comes back to the computer, it can be directed either to AIM (if it comes in on 5190) or the web browser (if it comes into port 80). If you are choosing a port manually for some reason, it doesn't usually matter what you choose as long as that port number is not in use by another program. Pick a big random number and you are safe. -DJ Craig