ipnat - user interface to the NAT subsystem
ipnat [ -dhlnrsvCF ] [ -M core ] [ -N system ] -f
  <filename>
ipnat opens the filename given (treating "-" as stdin) and
  parses the file for a set of rules which are to be added or removed from the
  IP NAT.
Each rule processed by ipnat is added to the kernels
    internal lists if there are no parsing problems. Rules are added to the end
    of the internal lists, matching the order in which they appear when given to
    ipnat.
Note that if ipf(8) is not enabled when NAT is configured,
    it will be enabled automatically, as the same kernel facilities are used for
    NAT functionality. In addition, packet forwarding must be enabled.
  - -C
- delete all entries in the current NAT rule listing (NAT rules)
- -d
- Enable printing of some extra debugging information.
- -F
- delete all active entries in the current NAT translation table (currently
      active NAT mappings)
- -h
- Print number of hits for each MAP/Redirect filter.
- -l
- Show the list of current NAT table entry mappings.
- -n
- This flag (no-change) prevents ipf from actually making any ioctl
      calls or doing anything which would alter the currently running
    kernel.
- -r
- Remove matching NAT rules rather than add them to the internal lists.
- -s
- Retrieve and display NAT statistics.
- -v
- Turn verbose mode on. Displays information relating to rule processing and
      active rules/table entries.
/dev/ipnat
/usr/share/examples/ipf Directory with examples.
ipnat(5), ipf(8), ipfstat(8)