NAT (Port Forwarding) and Spurious retransmission

[supabib]

Hi everyone,

I've set up PORT FORWARDING rules to redirect my web traffic (on my domain name) to my Traefik ReverseProxy. Following my issue, I re created my rules following : https://forum.opnsense.org/index.php?topic=6155.0.

Now the issue : on port 443 (https), everything works fine on https://httpd.mydomain.com

However, on port 80 (http), it's another story : I got timeout on my browser when trying to reach http://httpd.mydomain.com.

On destination server port 80 is opened and reachable from my OPNSense (curl get a server response HTTP 200).

I investigated : packets on ports 80 are seen by OPNSense which let them pass. So I installed Wireshark on destination server. HTTP packets do arrive on the server but, after the 1st 2 or 3 packets, exchanges are looping with  :
- TCP Retransmission from my server
- TCP Spurious Retransmission from my client (where resides my web browser).

Note that I make my tests with my mobile to be sure to not be on my LAN network.

Anyone can help?

Edit : I'm using OPNsense 18.1.13_1-amd64
Edit : replaced NAT with PORT FORWARDING, sorry for that