This section is designed to familiarize you with ipfilter's syntax, and firewall theory
in general. The features discussed here are features you'll find in any good firewall
package. This section will give you a good foundation to make reading and understanding
the advanced section very easy. It must be emphasized that this section alone is not
enough to build a good firewall, and that the advanced section really is required reading
for anybody who wants to build an effective security system.