ext_if="ng0"
int_if="re0"
int_net="192.168.1.0/24"
vpn_if="tap0"

ext_gw="109.195.67.254"
vpn_gw="172.16.0.1"

nat on $ext_if from !($ext_if) -> ($ext_if)
nat on $vpn_if from $int_if:network -> ($vpn_if)


pass out on $ext_if route-to ($vpn_if $vpn_gw) from $vpn_if to any
pass out on $vpn_if route-to ($ext_if $ext_gw) from $ext_if to any