title: Docker daemon config file on boot2docker / docker-machine / Docker Toolbox
body: <p>Where can I find docker daemon config file on boot2docker machine? </p>
  
  <p>According to this topic: <a href="https://stackoverflow.com/questions/25130536/dockerfile-docker-build-cant-download-packages-centos-yum-debian-ubuntu-ap">Dockerfile: Docker build can&#39;t download packages: centos-&gt;yum, debian/ubuntu-&gt;apt-get behind intranet</a> </p>
  
  <p>I want to set '--dns' in <code>DOCKER_OPTS</code>, but I can't find this config file either at <code>/etc/default</code> or anywhere else.</p>