While triaging #36510 (comment), I noticed that the current error message is rather cryptic, and doesn't provide enough information for the user to resolve the problem:

Error initializing network controller: list bridge addresses failed: no available network

When the daemon starts, it attempts to find if any of the standard private IP-ranges is available for docker to use (doesn't overlap with existing networks in your situation): 172.17-31.x.x/16, 192.168.x.x/20 or 10.x.x.x/24:

When failing to select a range, only the error above is printed.

I sugest we improve the error, and (if possible) call out:

• each IP-range that is tried
• a message explaining that Docker failed to automatically select an available IP-range
• possibly referring to the documentation: https://docs.docker.com/v17.09/engine/userguide/networking/default_network/custom-docker0/ (note: in the latest rewrite of the docs, I think some of that information has gone lost /cc @gbarr01)
• should we mention the "VPN" situation? (i.e. a VPN capturing all IP-ranges, causing detection to fail?)

Note that the detection is done in libnetwork; generally "libraries" should not do logging, so that's possibly something to take into account when implementing.

ping @fcrisciani @selansen PTAL if you have input on this; I'm assigning this exp/beginner and exp/intermediate - possibly a contributor wants to work on this