modprobe iptable_nat
iptables -N nat
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source *.*.*.*
iptables -t nat -A PREROUTING -i eth0 -p tcp --destination-port 21000 -j DNAT --to-destination 192.168.*.*
iptables -t nat -A PREROUTING -i eth0 -p udp --destination-port 21000 -j DNAT --to-destination 192.168.*.*
просто с етим и нот проблемс у меня