We're trying to harden firewall settings for a computer. We allowed only port HTTPS (443), NTP (123) and DNS (53).
Now we fail to send POST requests to a web api application unless we open port 80.
After we open port 80 and perform one successful request, we are able to work with the web api application for a while even if port 80 is blocked again.
Is it possible to leave only 443 allowed and perform HTTPS requests without ever allowing port 80?
Thanks for the answers!