Fat Client: A computing device, such as a PC or Macintosh, that includes an operating system, RAM, ROM, a powerful processor and a wide range of installed applications that can execute on the desktop or 100% on the server under a Server-based Computing architecture. Fat clients can operate in a server-based computing environment.

Fault Tolerance: A design method that ensures continued systems operation in the event of individual failures by providing redundant system elements.

File-infecting Virus: Some viruses infect executable files. There are a variety of mechanisms that they use to do so. Usually, the virus will get control when the program is first executed. In most cases, the virus will return control to the original program after it has completed its own execution.

Firewall: A system or combination of systems that enforces a boundary between two or more networks.

FIRST: Forum of Incident Response and Security Teams

Flooding Programs: Code which when executed will bombard the selected system with requests in an effort to slow down or shut down the system.

FTP: File Transfer Protocol, a standard Internet protocol, is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers.