Pyhomematic blocks HASS startup


I have my CCU running as a LXC container on a Pi2.
homematic configuration in HASS is minimal:


When I start HASS on my Windows machine using the same configuration - everything works as expected.
Today I moved HASS to a Synology DS using homeassistant/home-assistant::latest docker container.

Whenever I launch the container on the DS the initialization hangs at pyhomematic → Starting server at … and HASS is not available.

[32m17-01-03 19:43:44 INFO (Thread-4) [pyhomematic._hm] Creating proxy rf. Connecting to[0m
e[32m17-01-03 19:43:44 INFO (Thread-13) [pyhomematic._hm] Starting server at[0m

after about 4 minutes the proxy finished initializing

e[32m17-01-03 19:47:58 INFO (Thread-4) [pyhomematic._hm] Proxy initializede[0m

but no homematic components are available.

In addition it seems to block the CCU RPC server on the Pi.
Stopping the container and starting HASS on my PC again causes the HM Proxy creation on the PC to also hang for a while.

I enabled debug output for pyhomematic without seeing any hints pointing to a possible cause of this behaviour.

Any help appreciated.
Thank you

removed log

OK. I added some logging and found the issue.
I did only a port forwarding for 8123.

And so the pyhomematic proxy is created on a dockers internal IP:

e[36m17-01-03 20:47:35 DEBUG (Thread-7) [pyhomematic._hm] ServerThread.proxyInit: init(‘

After allowing the container to use the same network as docker - the homematic components show up and work as expected.
Can this be configured in any other way?