SonicWALL TELE3 SP, Руководство администратора

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Appendices Page 187
Appendix C - Introduction to Networking
Overview
This appendix provides a non-technical overview of the network protocols supported by the
SonicWALL and includes a discussion of Internet Protocol (IP) addressing.
It can be helpful to review a book on TCP/IP for an overview of protocols such as TCP
(Transmission Control Protocol), UDP (User Datagram Protocol), and ICMP (Internet Control
Message Protocol). The following book is recommended for beginner and intermediate network
administrators:
Teach Yourself TCP/IP in 14 Days Second Edition
Timothy Parker, Ph.D
SAMS Publishing
ISBN # 0-672-30885-1
Network Hardware Components
• Computers - IBM- compatible, MAC, notebooks, and PDAs
• Resources - printers, fax machines, tape backup units, and file storage devices
• Cables - crossover, ethernet
• Connectors - bridges, routers
• Network Interface Card (NIC) - a card installed inside a computer that physically con-
nects a computer to a network and controls the flow of data from the network to the com-
puter. The NIC has a port where the network cable is connected.
Network Types
• LAN stands for Local Area Network . Local area refers to a network in one location, Local
Area Networks connect computers and devices close to each other such as on one floor of
a building, one building, or a campus. LANs can connect as few as two computers or as
many as 100 computers.
• WAN ( Wide Area Network ) connects LANs together. The networks that make up a WAN
can be located throughout a country or even around the world. If a single company owns
a WAN, it is often referred to as an enterprise network. The Internet is currently the largest
WAN.
Firewalls
A firewall is a software or hardware system that prevents unauthorized outside access, theft,
deletion, or modification of information stored on a local network. Typically, unauthorized
access would be via an organization’s Internet connection.
Gateways
A gateway can be a computer that acts as a connector between a private internal network and
another network such as the Internet. A gateway used as a firewall can transmit information