When configuring ntp on an ESX host the time synchronisation fails when the ntp init script is run:
# /etc/init.d/ntpd start
ntpd: Synchronizing with time server: [FAILED]
Starting ntpd: [ OK ]
When querying with ntpdate the following error is reported:
# ntpdate -q 10.1.1.1
server 10.1.1.1, stratum 16, offset -19.643999, delay 0.02718
13 Jul 09:58:34 ntpdate[5415]: no server suitable for synchronization found
The Cisco router has the following ntp config:
ntp server 203.12.54.1
The Cisco reports its status as:
# show ntp status
Clock is unsynchronized, stratum 16, no reference clock
The Cisco router is not correctly synchronising with an upstream time source.
Add the ntp source command to resolve the issue:
ntp source Ethernet0/0