Background: A
firewall is a software program acts as a
protective barrier between your computer and a network (generally,
the Internet).
Firewalls inspect any network traffic that passes through them and
allow or deny access to your computer based on rules that you
set.
Firewalls were first developed in 1988 when the early Internet was
swept by the Morris worm. The worm was a primitive virus that spread
via the Internet and although it was benign, it demonstrated that no-one
(at that time) had any protection against such a form of attack.
Over the decades since then, though, firewalls have advanced quite considerably.
And today if you connect to the Net using any form of non-dial-up access
a firewall is as indispensable to your personal security as a good
anti-virus program and adware/spyware blasters.
Early firewalls generally required extensive rule-setting that demanded
a high level of technical knowledge and expertise. But contemporary firewall
software developers recognise that most people aren't network
gurus and have made the process of rule-setting fairly easy. And that's
a good thing, because a firewall with too loose a set of rules offers very
little protection at all.
Most firewalls are commercial software, but fortunately there are also several
very good ones which are completely free. Here's are four of the best:
Firewall Software