iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 3128

iptables -A FORWARD -p tcp --dport 4662 -j ACCEPT
iptables -t nat -A PREROUTING -i ppp0 -p tcp --dport 4662 -j DNAT --to 192.168.0.99 
iptables -A FORWARD -p udp --dport 4672 -j ACCEPT
iptables -t nat -A PREROUTING -i ppp0 -p udp --dport 4672 -j DNAT --to 192.168.0.99 

#Azureus:
iptables -A INPUT -p tcp --dport 6881:6889 -j ACCEPT
iptables -A OUTPUT -p tcp --sport 6881:6889 -j ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 6881:6889 -j DNAT --to-dest 192.168.0.99
iptables -A FORWARD -p tcp --dport 6881:6889 0d 192.168.0.99 -j ACCEPT
iptables -t nat -A PREROUTING -p udp --dport 6881:6889 -j DNAT --to-dest 192.168.0.99
iptables -A FORWARD -p udp --dport 6881:6889 -d 192.168.0.99 -j ACCEPT