I'm not sure if this is a docker issue or upstream issue with the Go libraries.

I have a private registry at 10.0.133.19. My docker daemon's environment has $http_proxy defined and $no_proxy includes "10.0.128.0/19". When doing "docker pull 10.0.133.19:5000/imagename", the docker pull operation still hits the proxy when it shouldn't.

Adding "10.0.133.19" to $no_proxy explicitly (rather than the CIDR notation) is our workaround for now, and docker pull operations no longer go through the proxy.