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Windows Firewall
A few years ago the majority of home and small business
computer users had likely never heard of a firewall. Today
you can't ignore the need to be protected by a firewall as
the computing environment has become increasingly hostile.
The initial release of Windows XP contained a product called
Internet
Connection Firewall (ICF). It was fairly well hidden
away and really received very little attention. I'd venture
to guess many users weren't even aware it existed, much less
had it enabled. Times have changed dramatically and running
a computer today without a firewall is equivalent to
computing suicide. So much so, in fact, that with the
release of Service Pack 2 for XP, ICF has been renamed
Windows Firewall and it is now enabled by default.
If you aren't familiar with a firewall and what it does,
think of it as a fence that surrounds a yard or a moat that
surrounds a castle. It provides an area of protection around
a specific area, in this case your computer, and limits
access to the area to one specific location that you
control. In an ideal situation the access point would be
controlled in both inward and outward directions, similar to
having guards on the inside and outside of the gate or
drawbridge checking everyone that enters or leaves. The
easiest way to tell if Windows Firewall is enabled and
actively protecting the system is to click Start > Control
Panel and then click the
Security Center icon. The first item listed in Security
Center (Fig. 01) will be Firewall. As you can see, Security
Center reports "Windows Firewall is ON", the default
setting.
Fig. 01
Normally I'm against applications being
enabled by default. I much prefer to be made aware of the
option to enable a program and then making an informed
decision based on whether or not it's best in my particular
situation. However, because there are so many systems out
there running totally unprotected I have to agree that
enabling Windows Firewall by default was a good decision.
Users that are already running a more sophisticated firewall
product will be well aware that Windows Firewall is enabled
by default and take immediate steps to disable it, while
those users with no third-party firewall protection will at
least have the benefit of Windows Firewall.
For those that want to modify the default
firewall settings or turn it off completely, the [Manage
Security Settings For] section at the bottom of Security
Center contains a Windows Firewall icon. Clicking it will
open the Windows Firewall property sheet shown in Fig. 02.
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The General Tab - The On and Off
settings are self-explanatory. One question that does
come up rather frequently is whether or not Windows
Firewall should be on if there is another firewall
installed and in use on the system. The answer is no.
Use one or the other, but not both. Using both will just
lead to conflicts and confusion between the two
firewalls. In this case, more is not better.
I'll talk more about exceptions in the
next section. For now just be aware this is the place
where you can prevent exceptions from being allowed by
using the [Don't Allow Exceptions] checkbox.
Fig. 02
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The Exceptions Tab - Somebody
could (and probably will) write an entire book about the
Exceptions tab (Fig. 03) alone; what it does, why it's
necessary, the reason it has certain default items and
not others, and a host of other things that go along
with it, but I'm going to try and make it short and
simple.
When you use certain programs to access
the internet you're actually sending a request (packets)
to another location for information to be sent back to
your location. The outgoing requests are tracked and
when information (packets) are sent back to your
location they are compared or matched up to the requests
you have sent. If it is a legitimate match the firewall
allows the information to pass through to your system.
If the information wasn't requested, it's stopped and
denied passage. So what does this mean in the real
world?
You may not ever have to worry about
adding or authorizing an exception. If you do run across
something that requires an exception (most likely an
internet game or an instant messaging application) a
dialog box will appear asking if you want to allow the
program access. Take a look at the name of the
application and think carefully. Do you really want and
need the application enough that you are willing to
grant it an exception? If so, follow the instructions in
the dialog box and you'll be all set.
Fig. 03
If you run across an application that
isn't working properly and you think it's related to
network access, try the [Add Program...] button and add
it to the exceptions list. The [Add A Program] window
(Fig. 04) will open and you can either select the
program from the list provided or use the [Browse]
button to locate the executable in another location.
Fig. 04 Once the program has been
selected the [Change Scope...] button can be used to
open the Change Scope dialog box (Fig. 05) where options
are available to set what computers are covered by the
exception. Once you're done, exit the series of dialog
boxes by using the OK buttons.
Fig. 05 In some cases, rather than adding
an application to the exceptions list you might want to
open an individual port instead. Referring back to Fig.
03, click the [Add Port...] button to open the [Add A
Port] dialog box (Fig. 06). Try to avoid this option if
possible. It's risky because the port remains open at
all times and compromises the security of the system.
Fig. 06
Finally, if the firewall becomes so
screwed up that you no longer have any idea what's up
and down or in and out, the [Restore Defaults] button in
the Default Settings section can get you back to the
default state the firewall is in when first installed.
Sometimes it's the only way out. Swallow your pride and
click it; you won't be the first and surely not the
last.
Fig. 07
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