For an example, I have two authorized client computers, 220.127.116.11 and 18.104.22.168. My server running iptables is 22.214.171.124 and my firewalled web server is 126.96.36.199. When one of the authorized client IPs connects to 188.8.131.52 on port 80, I would like the connection to be forwarded to 184.108.40.206 on port 8888. If any other IP attempts to connect I would like it to refuse/drop the connection. What iptables config would accomplish this? Is there something more specific out there that would be better suited for this job?
The forwarding can be done with DNAT. Just give a specific source address, and let the others be rejected/dropped as normal.