NC-AIO tries to connect to reverse proxy

Hi there,

I’ve installed nextcloud AIO behind a reverse proxy according to the documentation (reverse-proxy.md). Up to now everything is working ok.
However, I observed an issue regarding the connection from nextcloud towards the reverse proxy.

Let me explain:
The reverse proxy and nextcloud are sitting each in a separte server in a different subnet. In my firewall I allowed the reverse proxy to connect to the nextcloud server on port 11000. I am able to connect normally to the nextcloud server. However, the nextcloud web interface is loading very slow.
In my firewall logs I saw that the nextcloud server tries to connect to the reverse proxy server on port 443. This connection is, however, blocked by my firewall.
If I set a corresponding firewall rule that allows nextcloud server to connect to the reverse proxy server on port 443, the nextcloud web interface is loading much faster.

My question is: Why is the nextcloud server trying to connect to the reverse proxy server (initiate a connection)? Is there any reason to do so?

Best regards

good idea would be to check the logs of Nextcloud and reverseproxy.
the most obvious reason is Office/Collabora which will be checked frequently (and connects back to NC while editing files)… maybe there are more reasons…