I am running OMV 5 with Nextcloud in a Docker-image. I also installed the Fail2ban-plugin.
Fail2ban seems to work but it doesn't block the IP it should. I can still logon to Nextcloud after three tries.
I found an article where it is proposed to change the action to work on the "FORWARD-Chain".
So something like this. I don't know enough to realy understand this. Maybe somebody can explain it to me or propose another solution.
Actually I would suggest to somehow automate the Fail2ban-plugin to work with a Docker-image.
I forgot to mention that Nextcloud is behind a reverse-proxy. So thats why it's not working. It wasn't that. See last post.