@wts When creating a ~/.ssh/config
Host nickname
Hostname <IP>
it can successfully connect. (So not a routing problem, not a firewall issue. I am absolutely certain on that.)
I can successfully ping that IP as well from within the container. When I try to do the same with the hostname, I get a „bad ip“ response.
So at least that seems consistent.
Seems to be related to the capitalization of parts of the hostname.