iptables --flush
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain

iptables --table nat -A POSTROUTING  -o ppp0 -j MASQUERADE
iptables -A FORWARD --in-interface eth0 -j ACCEPT

iptables -A PREROUTING -t nat -p tcp --dport 4170 -j DNAT --to-destination 192.168.0.8:4170
iptables -A FORWARD -i ppp0 -p tcp -m state --state NEW -d 192.168.0.8 -j ACCEPT