[ Thanks to Steve
Litt for this link. ]
“Security and convenience. They’re usually a tradeoff. So it is
for firewalls. It would be most convenient to have the firewall
pass everything (in other words, no firewall at all). Trouble is,
in all but the most benign environments, your box would quickly be
owned. Ultra security would dictate the most selective possible
firewall. The downside of such an ultra-selective firewall is that
the slightest oversight would lead to a service not being
accessible, or possibly being slow or intermittent, and the
firewall wouldn’t be the obvious root cause. So we balance the
convenience we need with the security called for, and hopefully
come up with a proper firewall.“Modern Linux distributions use a program called IPTables for
firewalling. Daunting at first, IPTables becomes logical with a
little explanation and a little experience. That’s where this issue
of Linux Productivity Magazine comes in–it gives an explanation,
and if you follow the articles, you get a little experience…”