title: 2 iptables rules I don't understand
body: <p>Could anyone explain the following rules:</p>
  
  <pre><code>-A default-INPUT -p tcp -m tcp --sport 0:1023 ! --tcp-flags FIN,SYN,RST,ACK SYN -j ACCEPT
  -A default-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  </code></pre>
  
  <p>I think I added them to prevent SYN flood but I'm not sure.</p>