forward traffic with iptables

iptables-forward.info

# from http://www.debuntu.org/how-to-redirecting-network-traffic-a-new-ip-using-iptables

# enable ip forwarding until reboot
echo 1 > /proc/sys/net/ipv4/ip_forward
# enable ip forwarding after reboot
# edit /etc/sysctl.conf
# uncomment line: #net.ipv4.ip_forward=1




# forward all traffic incoming on port 1111 to 2.2.2.2 on port 2222
# note -- PREROUTING happens before traffic arrives at this box, so, on the box you are running this command on, 
# you cannot test it locally, ala: telnet localhost 1111 -- it won't work because the PREROUTING rule won't get called
iptables -t nat -A PREROUTING -p tcp --dport 1111 -j DNAT --to-destination 2.2.2.2:2222
iptables -t nat -A POSTROUTING -j MASQUERADE