When I was reading about web servers, I came to know that though servers listen to static port (say port 80 for http), immediately after the connection, they assign a different port and thread to process. This helps in scalability; otherwise the server cannot listen to the static port until the processing of the previous request is finished.
Now my question is that if you have a stateless firewall at the client side (I know it is not a common scenario), how can we configure this? We can allow outbound and inbound to/from the destination server at port 80. But since the target port is randomly assigned, we cannot be sure of the inbound port number. Since the firewall is stateless, it doesn't have any previous knowledge of outbound connection initiation. How do we configure this then? Thanks in advance.