Weird problems using HAProxy

[blue_shift]

Hi folks,

I got some problems with HAProxy that I cannot really solve somehow. Just the basics for the beginning, I am using my OPNSense behind another router - so I got an "IPoE" environment. I got Nextcloud working on
a virtual machine that works pretty fine using port forwarding (that I would like to replace using HAProxy).

INTERNET --> 443 --> ROUTER1 --> 8443 --> OPNSENSE > HAPROXY > 80 --> NEXTCLOUD
INTERNET -->  80  --> ROUTER1 -->   880 --> OPNSENSE > HAPROXY

I got another Nextcloud installation that is running on port 80, that I would like to connect. I thought I can run
HAProxy using the LE-certificates on port 443 and it should "forward" it internally to port 80.

But when I access the URI using port 443 I see in the firewall logs that port 880 is used (the ports 8443 and 880 are several public services in HAProxy)?! The port 880 is closed on the firewall but if I set an Allow-rule nextcloud works fine.

The conditions and rules seem to be correct. Another app that is using the same port externally and internally works totally fine. Seems just to occur on Nextcloud. The first router does it's job correct, if I switch to port forwarding all works fine - so it is HAProxy.


Thanks for your help and comments...