Just upgrading from 5.1 to 5.5 of the Vcenter Server Appliance and was wanting to set time synchronization

Get a list of public NTP server from http://www.pool.ntp.org/zone/au

Login to the upgraded VCSA as root and run ntpdate your.ntp.server.name.here will confirm that your VCSA can talk to the remote NTP servers

ntpdate 0.au.pool.ntp.org
15 Jan 00:55:47 ntpdate[12590]: step time server 45.76.113.31 offset 1.001278 sec
VCSA-MA-VC01:~ # ntpdate 0.au.pool.ntp.org
15 Jan 00:55:59 ntpdate[12624]: adjust time server 45.76.113.31 offset -0.000129 sec