title: iptables with docker blocking incoming traffic, allowing outgoing traffic
body: <p>I'm running a dockerized app on an ubuntu machine. It's a test environment so I want to limit acces to a few IP addresses. I use the following iptables rules:</p>
  <pre><code>iptables -I DOCKER-USER -p tcp --dport 80 -j REJECT
  iptables -I DOCKER-USER -p tcp --dport 443 -j REJECT
  iptables -I DOCKER-USER -p tcp --dport 3306 -j REJECT
  iptables -I DOCKER-USER -s &lt;my ip&gt; -p tcp --dport 443 -j RETURN
  iptables -I DOCKER-USER -s 172.18.0.0/16 -p tcp --dport 3306 -j RETURN
  </code></pre>
  <p>Works ok to block all traffic, except it also blocks all outgoing traffic, rendering e.g. api-calls to other systems useless. How can I block all incoming traffic on 443, and also allow outgoing traffic on 443?</p>