title: Docker for Windows: Invoke-WebRequest fails on docker build
body: <p>I'm currently playing around with Docker for Windows on a Windows Server 2016. 
  I wanna build a node.js image, but powershell is not able to connect to the remote server and download node.js.</p>
  
  <p>This is the part in my Dockerfile which fails:</p>
  
  <pre><code>RUN ["powershell", "Invoke-WebRequest -Uri https://nodejs.org/dist/v7.4.0/node-v7.4.0-x64.msi -OutFile nodejs.msi"]
  </code></pre>
  
  <p>and I'm getting the following error:
  <a href="https://i.stack.imgur.com/4WANU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4WANU.png" alt="docker build error"></a></p>
  
  <p>I'm behind a corporate proxy, but I've already configured the proxy and everything else like docker pull works.</p>