title: Allow routing to docker 172.17.0.0/16 network without NAT?
body: <p>I'm exploring Docker 1.7. Previously I used CoreOS (great project) which took all the headache of networking out of it.</p>
  
  <p>In CoreOS I'm able to set a static route for traffic that would go to docker's bridge network (i.e. 172.17.0.0/16 or whatever it picks) on my external router to point to the CoreOS host and it would just work.</p>
  
  <p>Using the latest and greatest docker running under CentOS 7 I'm trying to replicate this functionality however if I turn on ipv4 routing in sysctl and delete the masquerading rule from the nat postrouting table nothing works (a simple recycle of docker puts the rule back in, I'm assuming something in the docker config is not correct).</p>
  
  <p>Is there a way to configure docker to setup networking in this fashion (do I have to do this myself with a custom bridge interface or is there a config flag for it)? I can always wait for CoreOS to update to latest and greatest docker but I'd like to know how to configure it myself.</p>