Linux Exposed: Open Source Firewalls Explained

“Hackers have computers too and want to keep their own machines
free of intrusion from the Internet. Paradoxically, these computers
may be the most secure computers on the Internet, because the
hackers use free software that they can examine for security
problems, they are the first to discover (or create) security
weaknesses, and they fix their own systems as soon as loopholes are
discovered. They share the security fixes with anyone who wants
them, and you can take advantage of this fast response to new
threats in your own network by using the same software they do.
Hackers have computers too and want to keep their own machines free
of intrusion from the Internet. Paradoxically, these computers may
be the most secure computers on the Internet, because the hackers
use free software that they can examine for security problems, they
are the first to discover (or create) security weaknesses, and they
fix their own systems as soon as loopholes are discovered. They
share the security fixes with anyone who wants them, and you can
take advantage of this fast response to new threats in your own
network by using the same software they do. Free firewalls often
suffer from a few of the same class problems:

“Weak or missing logging and alerting features
No real-time firewall monitoring capability
Weak or missing graphical user interface
Difficult command prompt-based configuration…”

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