With my VPN client – Pulse VPN (https://www.pulsesecure.net/connect-secure/overview/) – previous versions of Docker for Mac “just worked” with my VPN. Pulse writes its DNS config to /etc/resolv.conf and Docker for Mac seemed to respect that.
It looks like with 1.13, Docker for Mac is now not respecting that file; instead looking at Mac network system preference settings? Pulse VPN does not show up as a network under system preferences.
I’m downgrading for now but would love to hear other options / more details on the DNS/VPN changes in this version.