# enable vpn_gw traffic to inet
ipt -A fw_vpn_gw -o $if_inet -j ACCEPT

# SNAT source IP to 91
ipt4 -t nat -A post_inet -s $if_vpn_gw_net4 -j SNAT --to ${if_inet_ip4arr[3]}

# accept ESTABLISHED from inet to vpn_gw
ipt -A fw_inet -o $if_vpn_gw -m state --state RELATED,ESTABLISHED -j ACCEPT