 the first datagram after we have 
sent one datagram.</p>
      <p><strong>Port-Restricted cone NAT</strong>: Same as 
address-restricted cone NAT, but we had to send to both the correct 
remote IP address and correct remote port. The same source address and 
port to a different destination uses the same mapping.</p>
      <p><strong>Symmetric NAT</strong>: A different port is chosen for 
every remote destination. The same source address and port to a 
different destination uses a different mapping.