6. What is libiptc?
libiptc is the library that is used to communicate with netfilter, the internal kernel code in charge of firewalling and packet filtering. This code and iptables were written by Paul "Rusty" Russell. iptables was developed using libiptc calls to get the job done.
If you want to have more information about iptables, libiptc and the firewalling code, have a look at links at the end of this document.