title: Proxy with self signed cert causing hosts to not be found during Docker build?
body: <p>I am behind a proxy server with a self signed certificate. I am able to reach docker.io/hub to fetch the latest centos image, but all other hosts seem to be unreachable. I had to set the proxy settings in /etc/sysconfig/docker and drop in the docker.io certificate chain downloaded from the browser into the docker certificate folder to even get that to work. Has anyone heard of this behavior, where all hosts are inaccessible because a proxy server has a self signed certificate? Again, I have set the proxy settings in /etc/sysconfig/docker. I still was unable to reach docker.io to do a docker pull centos until I dropped in the downloaded certificate files to docker.io from a browser to the docker certificate folder. Everything looked fine until I tried doing a build that did a curl statement trying to reach pkg.jenkins-ci.org. That host, and it seems all other hosts, other than the ones I specifically drop certificate chains into the docker certificate folder are unreachable. What can cause this? I have attached an image of a simple "docker build ." with the Dockerfile in the current directory.</p>
  
  <p><a href="https://i.stack.imgur.com/9gqFW.png" rel="nofollow"><img src="https://i.stack.imgur.com/9gqFW.png" alt="enter image description here"></a></p>
  
  <p>Redhat 7.2 on a virtual machine inside a private network using a proxy with a self signed certificate.</p>