Firewall: A firewall is used to keep other people from snooping around your computer. The internet was designed for people to communicate and share information. It does this via ports, which you can think of as doors or channels into your machine. When you send information out of your machine, you send it out through a port. These ports have numbers and some of them are standardized numbers. For instance, web pages come into your machine on port 80. There are thousands of possible ports on a computer. These are not real doorways, they are virtual doors. When you click on a link to a web page, your firewall watches and sees that you have made a request to receive information. When that web page loads on your machine, it is transferring data from another computer to your computer, a process that we call downloading. Your firewall lets the data in because it knows that it is data that you have requested. Firewalls monitor ports on your machine to ensure that nothing is allowed in which you have not requested or given permission to. Some applications, such as instant messaging programs, leave a port open and listen for incoming connections. If this were not the case, no one could ever send you an instant message because the firewall would block it. A firewall is a vital part of staying secure on the Internet today.*

Fishing: See phishing.

Instant Messaging: Instant Messaging is a program that runs in the background on your computer. It listens for connections from another computer called a server. (It serves you.) You have a list of contacts you add to your Instant Messaging (or IM) program because you want those people to be able to contact you when you are online. The server lets them know you are online, and also lets you know when they are online. They may then choose to initiate a conversation with you, or you can initiate a conversation with one of them. This is chatting. You type messages into a box and send it to them. They get this message very, very quickly and type back. Most IM programs allow you to talk or do video chat with another person as well.

[A - E] [F - J] [K - O] [P - S] [T - Z]