title: How to allow a domain name in iptables?
body: <p>I have a linux server that gets an time offset for some strange reason</p>
  
  <p>I set up cron job to run and update the time using the following command</p>
  
  <pre><code>/usr/sbin/ntpdate pool.ntp.org
  </code></pre>
  
  <p>The problem is the command would not run because I have a firewall (iptables)</p>
  
  <p>I have always use IP to allow traffic in my network:</p>
  
  <pre><code>iptables -A INPUT -p tcp -m tcp -i eth0 -s 11.11.11.11 --dport 5060 -j ACCEPT
  </code></pre>
  
  <p>I would like to know how to do it using a domain name in this case would be <code>pool.ntp.org</code></p>
  
  <p>Or maybe someone could tell me a better way to keep the clocks in sync</p>
  
  <p>Please advice</p>