title: Caddy 2 not running in Docker: "cannot assign requested address"
body: <p>I'm trying to run <a href="https://hub.docker.com/_/caddy" rel="nofollow noreferrer">the official Caddy 2 docker image</a>. According to that page, to do that you should run:</p>
  
  <pre><code>docker run -p 80:80 \ 
      -v $PWD/index.html:/usr/share/caddy/index.html \
      -v caddy_data:/data \
      caddy
  </code></pre>
  
  <p>When I run this, I get the following error:</p>
  
  <blockquote>
    <p>{"level":"info","ts":1590185286.853735,"msg":"using provided configuration","config_file":"/etc/caddy/Caddyfile","config_adapter":"caddyfile"}
    run: loading initial config: loading new config: starting caddy administration endpoint: listen tcp 45.90.28.0:2019: bind: cannot assign requested address</p>
  </blockquote>
  
  <p>I'm not sure why it's trying to bind to that IP address by default? I tried changing it in the Caddyfile but it still doesn't bind correctly, and anyway that doesn't really solve the underlying issue here.</p>
  
  <p>What could be causing this problem? Should I be using Caddy 1 instead?</p>