In the global world of Internet, firewall is the !"#$%&'( core
technology of today’s network security and first line of defense
against external network attacks and threats. Firewall controls
or governs network access by allowing or denying the
incoming or outgoing network traffic according to firewall
policy rules. These rules are explicitly written and managed to
filter out any unwanted traffic coming into or going from the
secure network. However, the management of firewall rules
has been proven to be complex, error-prone, costly and
inefficient for many large-networked organizations. These
firewall rules are often custom-designed and hand-written by
and for the human policy writer of an organization and tailored
to accommodate ever-changing business and market demands
of the global Internet. Therefore, these rules are in a constant
need of updating, tuning and validating to optimize firewall
security.