Basic PF Config Example Cont.
Kyle Amon,  Page 11
/etc/nat.conf

  rdr on rl1 from any to any port 21 -> 127.0.0.1 port 2121
  nat on rl0 from 192.168.0.0/16 to any -> 1.2.3.4

/etc/inetd.conf

  127.0.0.1:2121 stream tcp nowait root /usr/libexec/ftp-proxy ftp-proxy