Miscellaneous NAT Configuration Tips

Don't forget to add "net.inet.ip.forwarding=1" to /etc/sysctl.conf or NAT will
not work.  NAT requires IP packet forwarding.

Don't forget to add "option IPFILTER" (and maybe "option IPFILTER_LOG"
if you want ipmon(8) to work) to the kernel config file or NAT will
not work.  NAT requires the IPF packet filter.

You must have IPF enabled even if you aren't using it for anything or
NAT will not work.  The standard way to do this is to make sure
/etc/ipf.rules is installed and edit /etc/rc.conf changing
"ipfilter=NO" to "ipfilter=YES" then reboot.