What is a Firewall ?

By: Benjamin Hargis

Simply put it acts as a barrier between your computer and the
internet. To protect you from crackers, hackers and malware.

If your running DSL or a cable modem you should employ a
firewall, as having a direct connection to the Internet can make
you a target to attack.

Firewalls can be hardware or software based. With firewalls you
set up ACL's or Access Control lists to allow or deny traffic.

There are three different ways a firewall can block traffic.

1. Packet Filtering- Packets are analyzed against filters in the
firewall rulesets. Firewalls will drop packets that are not
allowed in the firewall rulesets.

2. Proxy Service- Information from the Internet is grabbed by
the firewall and delivered to the requesting service thru the
proxy.

3. Statefull packet inspection- looks up criteria against a
database of trusted information. To see if the packet contains
anything that would allow

or deny it into the network.

Firewalls are customizable allowing you to create your own
rulesets you can block IP addresses, specific protocols such as
Telnet, FTP, ICMP, UDP, SMTP and many others.

Firewalls can be customized to block specific ports, or even
keywords.

There are many software firewalls availiable such as Tiny
Firewall http://www.tinysoftware.com/home/tiny2?la=EN That is
designed to keep hackers out of your network and block Spyware.

Zone Labs makes ZoneAlarm I like it bcause it has a simple
interface allowing home users to configure it easily.
http://www.zonelabs.com/store/content/home.jsp

For hardware firewalls there is:

Cisco www.cisco.com There brand is called PIX firewall.

From home users I like D-Link DI-604 this is a inexpensive
firewall that works well. Best of all it fits into almost any
budget.

Linksys (now part of Cisco) offers a router/firewall that
supports VPN and DMZ. www.linksys.com

There are many hardware solutions including setting up a
firewall on a *nix box. I like this the best as it gives you the
firewall administrator the most control. I personally like
OpenBSD for any security applications I would run with Unix, as
it is secure. There have been very few exploits against this
platform.

I will be writing more articles about firewalls shortly.

Benjamin Hargis CEO

Phuture Networks

http://www.phuturenetworks.com blog
http://phuturegenius.blogspot.com

email: ceo@phuturenetworks.com

About the author:
I'm a computer secuity consultant for home and small businesses.
I started a company called Phuture Networks to help home users
and small business owners about computer and network security.
During the day I consult Realtors on website design, hosting and
search engine optimization for a big company