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An internet firewall can help prevent outsiders,
such as hackers, from accessing your computer via the internet. If intruders
are allowed inside your system (unknowingly, of course!), they can be quite
difficult to stop and can change or delete files, use your computer to send
unwanted emails to others, launch attacks on others, and generally cause
damaging effects.
Firewalls come in two forms: hardware and software. A hardware-based firewall
is usually a router, or a personal computer that's
been tweaked to act as a firewall to the rest of your home network. Today,
however, many internet firewalls used in the home or small office setting are
software-based. These firewalls can be acquired from a third party, such as
Zone Labs' ZoneAlarm. Or, they
might already be built into your operating system, such as ICF (Internet
Connection Firewall) or Windows Firewall in Microsoft Windows XP, depending
on which service pack you have installed.
If you don't use a firewall, attackers can find and attack your computer
within 15 minutes of connecting to the internet. If you use an "always-on"
form of internet access, such as cable modem or xDSL (digital subscriber
line), it's especially important that you install a firewall and keep it up
to date.
Hardware firewalls
Hardware firewalls sit between your computer and your connection to the
internet. Routers are currently the most popular form of hardware firewall. A
router is a small device with usually four or more ports on the back into
which you plug in Ethernet cables. If purchasing a router, you should select
one that has more than enough ports to accommodate the number of computers on
your home network.
Some cable and xDSL modems have built-in firewalls, as do many WAPs (wireless
access points). Read the manual that came with your equipment or call the
manufacturer's technical support department to find out.
Installing a hardware firewall can be done quickly and easily. For example,
assume you have a cable or xDSL modem that you use to access the internet,
and your modem does not have a built-in firewall. To install a hardware
firewall, such as a router, do the following:
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Plug an Ethernet cable, such as the commonly used Category 5, into the NIC
(network interface card) on your computer.
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Plug the other end of the cable into an Ethernet port on the back of the
router.
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Plug a second Ethernet cable into a second port on the router and the other
end into the back of the cable or xDSL modem. Voila!
Immediately after you set up your router/firewall, change the default user
name and password; the defaults are well-known.
If you use a wireless router, enable the 128-bit WEP (Wired Equivalent
Privacy) encryption key for more protection. Without it, your neighbors could
connect to your wireless home network without your knowledge.
When considering a hardware firewall, note that many of the popular makes and
models, such as the
Linksys BEFSR41 4 Port Cable Router, should run under $60. Compare that
to the cost of replacing the data on your computer and the value of your time
spent cleaning up after your computer's been hacked -- you may find that $60
is well worth it.
Software firewalls
If you have dial-up access to the internet, you don't need a hardware
firewall. However, you do need a software-based firewall. Software firewalls
are popular with the home user community and available from a wide variety of
vendors. Many vendors offer free software to home and educational users, or
at least free trial versions. These vendors include, but are not limited to,
the following:
To set up a software firewall, do the following:
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Disconnect your computer from the internet.
It's best if you can complete firewall installation before you've ever
connected to the internet, but that's not always possible.
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Enable your operating system's firewall or acquire a third-party software
firewall and install it:
If it's built into your operating system: For
example, to enable Windows Firewall in Windows XP with Service Pack 2
installed, click Start > Control Panel >
> Windows Firewall. In the Windows Firewall
dialog box, click the On (recommended) option, and
then click OK.
If it's third-party software: Install the software
according to the manufacturer's directions. Usually, it's as simple as
clicking an Install button in the software
interface or locating and double-clicking the Setup.exe file.
After installing a firewall, you need to check the settings to make sure
you're indeed as protected as possible. This can be tricky sometimes, so if
you need help, don't hesitate to ask a knowledgeable friend or the
manufacturer's technical support staff.
Sometimes if you set the firewall filters too high, you spend more time
allowing traffic in and out than working. You may have to re-adjust the
settings as you get used to the firewall settings.
With a firewall in place between your computer and the internet, you're well
on your way to much improved computer security. However, don't rely only on
your firewall for protection. A firewall can be breached, and once that
happens, you'll need to fall back on other computer security measures to
defend your computer's resources against intruders.
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