Cells v4: Detection of private network interface failes
In Cells 3.x there is a loop over all network interfaces and the first interface found that matches the (your) definition of a private interface is returned.
With Cells v4 the loop is gone. The first interface found will be tested and most of the time it will detect a non-private interface resulting in a warning that there is no private interface, thus it will expose the grpc API to the public.
I personally would like to have the ability to tell the Cells process which private interface to use rather then letting the software decide.
Thanks for reporting. We'll have a look at this ASAP.
Fixed in 685b5d3510b0da25c5228241582c0463f0f50d59