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Written by Tony Phelps
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Thursday, 17 November 2005 |
Firewall software is quickly becoming a necessity in our
internet-enabled world. Even remote locations at the end of relatively
slow internet connections like Vanuatu need protection from those who
would like to pry into our computers from afar, or make use of our
computers for their own purposes. Firewalls provide that protection.
One suggestion for the origin of the term “firewall” is that it comes
from the 1800’s when fire-resistant walls were put up in warehouses to
slow or stop the destruction in the days before fire engines. Firewalls
can these days be seen in cars & planes, and of course, as a
program in computers.
Computer firewalls can be thought of as police, standing between the
“inside” and the “outside”. They monitor anything coming in or going
out, and if they don’t like it, they stop it. As is usual in the
over-complicated world of IT, what exactly the firewall is all depends.
Microsoft Windows XP now has a firewall built in & switched on by
default, and it is all but invisible. Separate devices can be purchased
that can only function as a firewall. And applications can be purchased
& installed that behave as enhanced firewalls, that are capable of
monitoring emails for viruses amongst other extra facilities.
Without a firewall, a computer connected to the internet allows access
to all sorts of things. Go to www.grc.com and look for the Shields Up
link, and run some online tests that show how vulnerable your computer
is. If there’s no firewall in the way, you will be amazed. It’s like
every computer has a couple of thousand “doors”, some are open, some
are shut but not locked, some are only weakly locked. Get a firewall,
and it’s like putting a big padlock on all the doors you don’t use, and
a big bouncer on the ones you do.
Generally, most people will want to be able to surf the internet, send
& receive emails, and maybe do some instant messaging. Even for
dialup users that are only connected temporarily, a firewall blocks the
use of a wide range of “doors” (called ports) and keeps a list of which
programs are allowed to use the internet. This not only stops the bad
guys from breaking in to the computer, but can help stop viruses or spy
programs sending stuff out.
Above all, for anyone with a permanent internet connection, whether
private, business or government, a firewall is essential. Permanent
connections are constantly scanned by automated applications from all
round the world. If they see you, they will come knocking! |
