dnat.md

To DNAT the traffic from 10.1.1.1:5432 to 192.168.1.1:5432 using iptables, you can follow these steps:

1. Enable IP forwarding:

   sysctl net.ipv4.ip_forward=1

2. Create the DNAT rule:

   iptables -t nat -A PREROUTING -i ens4 -p tcp --dport 5432 -j DNAT --to-destination 192.168.1.1:5432

   This rule tells iptables to redirect incoming TCP traffic on port 5432 of the ens4 interface to the destination IP address and port 192.168.1.1:5432.

3. Enable masquerading (Source Network Address Translation) to rewrite the source IP address:

   iptables -t nat -A POSTROUTING -o ens4 -j MASQUERADE

   This rule ensures that the response packets from the destination IP address are properly routed back to the client through the ens4 interface.

4. Save the iptables rules:

   iptables-save > /etc/iptables/rules.v4

   This command saves the iptables rules so that they persist after a reboot.

Make sure to replace ens4 with the actual interface name for the proxy server and 192.168.1.1:5432 with the IP address and port of your Postgres instance.