If you spend a lot of time on the internet
and you are not behind a firewall, then you are living
on borrowed time. Putting some protection between
you and the internet is probably the third most important
thing that you can do (after getting virus checking
software and performing regular backups).
The diagram to the left shows an unprotected
system using a DSL modem. As you can see, someone
on the internet can attach the computer system easily
as the DSL modem provides no protection (some DSL
modems have built-in firewalls). An attacker can get
through any type of modem - DSL, cable, 56K, 28.8
or whatever. If the device gets you on the internet,
you are vulnerable.
For those with a DSL, cable modem or
other "always-on" connection, you MUST get a firewall.
This is critical, as your machine is always live and
it most likely has a fixed IP address. This makes
it easier for your system to be "found" and attacked.
What a personal firewall does is isolate
your computer from the rest of the internet. It does
this by inspecting each packet of data to determine
if it it should be allowed to get to (and in some
cases from your machine.) The best protection completely
hides your computer - this is called stealth mode.
You have the option of installing a
software firewall or a hardware firewall.
Software Firewall - A software firewall
runs on your computer system in the background. It
intercepts each network request and determines if
the request is valid or not. Software firewalls offer
the following advantages:
- They are generally very inexpensive
- They are very easy to configure They have the following
- Since they run on your computer they require resources
(CPU, memory and disk space) from your system.
- They can introduce incompatibilities into your operating
- You must install exactly the correct version for
your operating system.
- You must purchase one copy for each system on your
Hardware Firewall - A hardware firewall
is generally a small box which sits between your computer
and your modem. In general, hardware firewalls have
the following advantages:
- They tend to provide more complete
protection than software firewalls
- A hardware firewall can protect more than one system
at a time
- They do not effect system performance since they
do not run on your system.
- They are independent of your operating system and
They have the following disadvantages:
- They tend to be expensive, although if you have
a number of machines to protect it can cost less to
purchase one hardware firewall than a number of copies
of a software product.
- Since they do not run on your computer,
they can be challenging to configure.
Firewall mixture - In my mind, the
best protection is a combination of both hardware
and software firewalls. This is the ideal, since both
have different advantages and disadvantages. Personally,
I use a SonicWall hardware firewall combined with
ZoneAlarm Pro, which is installed on my Windows 2000
Professional system. The SonicWall protects my home
network since it sits between the hub and the DSL
modem, and ZoneAlarm Pro offers some additional protection
for each system.
Testing Your Firewall - To test your
firewall, surf to http://www.grc.com and request a
probe. You will be given a very good report of exactly
what issues were found and what to do about them.
Once the probe is finished several excellent personal
firewall products are recommended. My personal favorite
is ZoneAlarm Pro, primarily because it's protection
is excellent and it is trivial to use.
Some Firewalls - A selection of personal
firewalls is listed below.
- ZoneAlarm Pro - By far the best software
firewall available. ZoneAlarm offers protection from
both incoming connections and outgoing connections.
It is also extremely easy to configure, has low system
impact and is very inexpensive (a free version is
- Norton Internet Security 2001 (which
was the AtGuard product from WRQ until a few months
ago). Norton is a reasonable firewall, although it
does have some vulnerabilities. It offers weak protection
from outgoing connections and is somewhat difficult
to configure if you want it to operate differently
from the default.
- BlackIce - A good choice in firewalls.
Much easier than Norton to configure, but with the
same vulnerabilities. What I've done on my system
- Used a SonicWall hardware firewall
to protect my entire home network. - Installed ZoneAlarm
Pro on ach system to provide additional safety
- And installed Norton Internet Security
for it's privacy protection.
Due to the rapidly changing nature
of the internet, it's very important to be continually
monitoring security issues. You may purchase the perfect
personal firewall today, only to find out in six months
that it's been hacked to pieces. So be sure to be
looking around, and be ready to get a newer and better
product quickly. This is not one of those issues where
you can scrimp and save. Your system is at risk.
About the author:
Richard Lowe Jr. is the webmaster of Internet Tips
And Secrets. This website includes over 1,000 free
articles to improve your internet profits, enjoyment
and knowledge. Web Site Address: http://www.internet-tips.net