# DNAT (rewrite destination IP and port) - PREROUTING chain
sudo iptables -t nat -A PREROUTING -p tcp --dport 22 -j DNAT --to-destination <dest_server_ip>:<dest_port>
# SNAT (rewrite source IP) - POSTROUTING chain
sudo iptables -t nat -A POSTROUTING -d <dest_server_ip> -p tcp --dport <dest_port> -j MASQUERADE
<dest_server_ip> = The server you want to get too.
<dest_port> = The server port you want to get too.
***You need both DNAT and SNAT for the port forwarding to work and make sure First, verify that IP forwarding is enabled. You can check this by running the command sysctl net.ipv4.ip_forward.
nano /etc/sysctl.conf to change
If it's not set to 1, enable it temporarily by running sysctl -w net.ipv4.ip_forward=1.
Use cmd - sysctl -p to check if port forwarding is on
iptables-save > /etc/sysconfig/iptables = Once you have everything the way you want it.