The Filter Language Compiler (flc) generates rules for the various
packages which perform packet filtering from a common language.

flc supports:
    IP Filter (full support - 2.8.1)
    ipfw (Linux - 1.3.6Beta3)
    ipfwadm (Linux - 1.2)
    ipfirewall (Linux/*BSD - 2.0e)
    Cisco (extended access-lists)
    screend
