port forwarding using ip tables

forward.sh

#!/bin/bash

read -p "Enter your proxy server's IP: " PROXY_IP
read -p "Enter your destination server's IP: " DEST_IP

sysctl net.ipv4.ip_forward=1
iptables -t nat -A PREROUTING -p tcp --dport 22 -j DNAT --to-destination $PROXY_IP
iptables -t nat -A PREROUTING -j DNAT --to-destination $DEST_IP
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables-save