About Firewalls...

[Walts]

Firewalls are...
...and with a "Tip O' the Hat" to Whatis?com

"A personal firewall (sometimes called a desktop firewall) is a software application used to protect a single Internet-connected computer from intruders. Personal firewall protection is especially useful for users with "always-on" connections such as DSL or cable modem. Often compared to anti-virus applications, personal firewalls work in the background to protect the integrity of the system from malicious computer code by controlling Internet connections to and from a user's computer, filtering inbound and outbound traffic, and alerting the user to attempted intrusions.

"In a network environment, a firewall is a set of related programs, located at a network gateway server, that protects the resources of a private network from users from other networks. An enterprise with an intranet that allows its workers access to the wider Internet installs a firewall to prevent outsiders from accessing its own private data resources and for controlling what outside resources its own users have access to.

"Computer security borrows this term from firefighting, where it originated. In firefighting, a firewall is a barrier established to prevent the spread of fire."

As to DSL...
"DSL (Digital Subscriber Line) is a technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. You may be able to receive data at rates up to 6.1 megabits (millions of bits) per second (out of a theoretical 8.448 megabits per second). More typically, individual connections will provide from 1.544 Mbps to 512 Kbps downstream and about 128 Kbps upstream. A DSL line can carry both data and voice signals and the data part of the line is continuously connected."

As to Cable Modem...
"A cable modem is a device that enables you to hook up your PC to a local cable TV line and receive data at extremely fast speeds at over 1.5 Mbps. Typically, the cable modem attaches to a standard 10BASE-T Ethernet card in the computer. The actual bandwidth for Internet service over a cable TV line is up to 27 Mbps on the download path to the subscriber with about 2.5 Mbps of bandwidth for interactive responses in the other direction. However, a more likely data rate will be close to 1.5 Mpbs."

As to a Gateway...
"A gateway is a network point that acts as an entrance to another network."

As to an Intranet
"An intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks. Typically, an intranet includes connections through one or more gateway computers to the outside Internet. The main purpose of an intranet is to share company information and computing resources among employees, in what generally looks like a private version of the Internet."

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