6. Firewall – Firewalls create barriers in order to prevent unauthorized access to a computer or network.  The Internet can be presented as a series of hallways.  Firewalls are the security doors through which some people (i.e. data) may pass and others may not.

Reasons:

• Protect the computer from hacker attacks;

• Protect the data in the computer from hacker attacks – passwords, credit card numbers, etc.

Types of firewall:

• Corporate firewalls – filter the packets by their TCP/IP ports.  They protect the Local Area Network that has Web, E-mail, FTP servers accessed from the Internet and are complex to configure and support;

• Personal firewalls – block unauthorized access to the computer.  They protect a single machine from hacker attacks and are simple to install configure;

• Software firewalls – for most popular see the next paragraph, Internet Resources;

• Hardware firewalls – most popular are LinkSys and D-Link Systems.

Internet Resources:

• What is a firewall?;

• Top Firewall Products from ZDNet Search - reviews, current prices, etc.;

• Firewall Products from CNET Search;

• Security on Cable Modem or DSL for Microsoft Windows

• Personal Internet Firewalls that really work

• Cable/DSL Info from Linksys;

• Cable/DSL Info from D-Link.