As with every protocol within the world wide web, the NTP and SNTP protocols use standard ports. NTP uses port 123 and SNTP uses port 37.
But sometimes the port that the protocols use differs from the standard one. You can
define the port which has to be used for each server within the address. Just add the
number of the port after the address. If no port is defined, then
Zend_TimeSync will use the standard port.
<?php
$server = new Zend_TimeSync(array('generic' => 'ntp:\\0.pool.ntp.org:200',
'fallback' => 'ntp:\\1.pool.ntp.org'));
$server->addServer('sntp:\\internal.myserver.com:399', 'additional');
print $server->getDate()->getIso();