Webdav

Hi,
I'm trying to publish a folder on a QNAP NAS Device via Webdav.

It is working from inside the LAN.
It is not working via SSL VPN, if I use any port other than 80.
It is not working vis SSL VPN if I use port 80 but disable web filtering.

With enabled web filtering, setting "allowed networks" to any and port 80, it is working vie SSL VPN.

My problem is, I cannot get it to work from outside the LAN without vpn.

I've created a DNAT rule, forwarding all traffic from an additional address using http to the QNAP device.

Two packet filter rules allow http for the QNAP device inbound and outbound to any...

Does anyone have an Idea what I could check?

Thanks in advance and best regards,
Matthias