Docker for windows: “server misbehaving” when trying to pull

Question

I\'m trying to run docker on windows (OS: Microsoft Windows 10 Pro 64bit, Docker ver: 18.09.0, build 4d60db4), by following the hello-world instruction here. Then I got thi

Answer 1

I have accepted the above answer but, for an unknown reason, the problem reappeared after a few days with a slightly different error. Luckily I managed to solve it using a different setup, as written below. Hope it can help someone when the accepted answer does not work.

First of all, the condition where this error happens: CNTLM listens to 127.0.0.1:3128, docker proxy (set through the GUI) is 127.0.0.1:3128 both for HTTP and HTTPS

Error response from daemon: Get https://registry-1.docker.io/v2/: proxyconnect tcp: dial tcp 10.0.75.1:3128: connect: connection refused

I checked this similar case but the solution also did not work for me. I tried several different things including turning off firewall, and reproducing the initial problem (my initial question) and redoing the accepted solution, to no avail. I realized that the IP address shown in the error is not my corporate proxy, nor the Cntlm-listened port, nor my localhost, but the IP of the dockerNAT.

Then, I also noticed that when running CNTLM -g -v, below the Cntlm ready, staying in the foreground line, nothing showed up when I run docker pull hello-world (in another terminal).

Inspired by this answer, I tried to change the Cntlm.ini and the proxy setting on docker to 10.0.75.1:3128, and then restarted cntlm and docker. Now things changed slightly. The error message changed to this:

Error response from daemon: Get https://registry-1.docker.io/v2/: Parent proxy unreacheable

and Cntlm terminal now showed something when I hit the docker pull command, indicating that it somehow works. I suspected that the proxy hostname might cause the problem at this stage, since docker might not be able to access DNS server from the VM. Then I changed Cntlm.ini again, changing the hostname of the proxy into its IP address, and voila, now docker pull hello-world works normally!

(TBH I don't fully understand the network theory behind why this solution works. If anyone can give some explanation, that would be helpful.)