Redirect traffic incoming on a specific port to a different IP address / another server
iptables -t nat -A PREROUTING -p tcp --dport 3124 -j DNAT --to-destination 18.104.22.168:3000 iptables -t nat -A POSTROUTING -j MASQUERADE
Below will show you how to redirect port 3124 on one machine to port 3000 on a different machine / IP address.
This can be useful for firewall related reasons.
iptables -t nat -A PREROUTING -p tcp --dport 3124 -j DNAT --to-destination 22.214.171.124:3000
This will route traffic incoming on port 3124 to 126.96.36.199 on port 3000.
You can put in any port or IP address you need there.
iptables -t nat -A POSTROUTING -j MASQUERADE
We set MASQUERADE to mask the IP address of the connecting system and use the gateway IP address instead. This is necessary for it to communicate back to the gateway, then to your client.
That is all that is required to get this to work.
service iptables save
This will save the changes, so they are persistent after a reboot.