WatchGuard Technologies WatchGuard Firebox SOHO 6 - Manual (Page 22)

Chapter 1: Introduction
4 WatchGuard Firebox SOHO 6.1
and the trusted network (your computer) and blocks any
suspicious activity.
How Does Information Travel on the Internet?
All information transported over the Internet is packaged in a
special manner to ensure that it travels from one computer to the
next. The program responsible for this task is known as TCP/IP.
TCP (Transmission Control Protocol) manages the assembly and
reassembly of data, for example an email message or program file,
into smaller chunks of data called packets. IP (Internet Protocol)
takes these packets and wraps them up with a header identifying
both where the information is going and how it is handled en
route.
IP addresses
An IP address defines the specific computer on the Internet that
sends or receives a packet. Every computer on the Internet has a
unique address, including your SOHO 6. When defining a service
behind a firewall, you need to include the trusted, network address
for the computer hosting the application.
On the Internet, IP addresses are identified using a string of
numbers that have been translated from a URL (Uniform Resource
Locator) name such as, www.watchguard.com.
Protocol
A protocol defines how a packet is bundled and packaged for
shipment across a network. The most commonly used protocols
are TCP and UDP (User Datagram Protocol). In addition, there are
a variety of IP protocols that are less frequently used.