title: Can't save iptables rule on Google Cloud VM instance (CentOS 7)
body: <p>I'm running Tomcat8 on CentOS7 in Google VM instance on port 8080.
  I setup the iptables rule to map all external connections to port 80 to 8080</p>
  
  <pre><code>iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080
  </code></pre>
  
  <p>After that I save the rule with </p>
  
  <pre><code>service iptables save
  </code></pre>
  
  <p>Tomcat works fine and accessible from outside via port 80.
  The rule is saved in <code>/etc/sysconfig/iptables</code>.</p>
  
  <pre><code>...
  -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 8080
  ...
  </code></pre>
  
  <p>but after server reboot the rule is not applied.
  It's still in the file <code>/etc/sysconfig/iptables</code> but not in action when I run</p>
  
  <pre><code>iptables-save
  </code></pre>
  
  <p>It seems that iptables rules are restored from somewhere else.</p>
  
  <p>How can I persist the rule properly to preserve it after reboot?</p>