@the-other ,
Thank you for your answer, and sorry for the late response.
I have just finished some experiments with firewall rules.
Based on your advice, I moved all rules from the generic OpenVPN tab to the OVPN1 tab, leaving no rules at that tab. Everything works in the same way compared to the previous configuration.
I also read that page in the pfSense manual you shared before I raised my post, but I did not fully understand. After reading your example, it became clearer, and after the mentioned experiments with rules, it is fully clear.
Hopefully, all my findings are correct:
Rules on the OpenVPN tab have priority over the OVPN1 tab (=> In case an incoming packet matches some OpenVPN tab rule, OVPN1 rules are ignored => Rules on the OpenVPN tab are meant to be generic and common for all OpenVPN servers.)
If there are no rules on the OpenVPN tab, there is a default message saying "No rules are currently defined for this interface
All incoming connections on this interface will be blocked until pass rules are added. Click the button to add a new rule". This confused me. I was convinced that a state without any rule is fully equivalent to a state with a "block all" rule (IPv4+IPv6, any protocol, any IP, any port, etc.). But at least for the OpenVPN tab, this is not true, as I tested that in case there are no rules on the OpenVPN tab, rules from OVPN1 are applied, and everything just works. I just tried to add a "block all" rule on the OpenVPN tab, and remote clients lost connection. So the mentioned message is quite confusing in this case. Because if that message was correct, remote clients would not have had a connection.
Thanks,
Jan
