Hello again!
I have resolved my problem by myself :D:
There have been two reasons for this “silly” error constellation:
1. the mDNS service on the ubuntu server was disabled
Explanation: the SB uses the mDNS protocol (multicast domain name service) to make an address resolution. If there is no mDNS server running, SB cannot connect to the firefly server.
I switched the service on again, but I didn’t get it work at all:
2. In the last days I have configured a virtual eth interface:
In the last days I have played a little bit with openVPN und ipsec. For that I created a virtual ethernet interface.
After starting the mDNS service again, the mDNS responses are sent to the virtual ethernet interface, not to the primary real one. After disabling the virtual interface everythins works fine.
Thanks a lot to the developers of wireshark ;).
Yours
Markus