ESX NTP Troubleshooting

Problem

The collector is unable to poll an ESX host via the NTP datasource. 

Cause

This can be due to the ‘noquery’ access restriction being present within the ESX host’s ntp.conf. 

Solution

1. Verify NTP works locally from the ESX host’s CLI, using the ‘ntpq -p’ command:

~ # ntpq -p
 remote refid st t when poll reach delay offset jitter
 ==============================================================================
 +123.108.200.124 103.252.195.20 3 u 46 64 377 81.459 4.968 3.615
 *web10.hnshostin 158.43.128.33 2 u 44 64 377 38.879 5.120 5.157

2. Attempt to query with the nptq executable located within \Agent\lib on the host the collector is installed on. This can be done from the terminal or command prompt, and should be run against the device you’re troubleshooting. For example:

C:\Program Files (x86)\Logicmonitor\Agent\lib\ntpq.exe -nc peers 192.168.1.100
192.168.0.100: timed out, nothing received
***Request timed out

This indicates it works locally, but not remotely. 

3. Check ntp.conf of the ESX host, specifically looking for the restriction ‘noquery’. If it is present, edit and remove it. For example: 

 ~ # cat /etc/ntp.conf
 restrict 127.0.0.1
 restrict default kod noquery nomodify notrap
 server 0.pool.ntp.org
 server 1.pool.ntp.org
 driftfile /etc/ntp.drift

to

 restrict 127.0.0.1
 restrict default kod nomodify notrap
 server 0.pool.ntp.org
 server 1.pool.ntp.org
 driftfile /etc/ntp.drift

4. Repeat step 2, and verify NTP responds from nptq.exe:

C:\Program Files (x86)\Logicmonitor\Agent\lib\ntpq.exe -nc peers 192.168.1.100
 remote refid st t when poll reach delay offset jitter
 ==============================================================================
 +123.108.200.124 103.252.195.20 3 u 46 64 377 81.459 4.968 3.615
 *web10.hnshostin 158.43.128.33 2 u 44 64 377 38.879 5.120 5.157

Further reading: