If the host has the NTP service enable but don’t send any data to the query, the server is configured correctly.
ntpq -pncrv 192.168.123.12 timed out, nothing received ***Request timed out
But … if you send a query and get information back… the server is vulnerable to attacks.
Obtain kernel information and other NTP server parameters.
ntpq -pncrv IP
Example:
ntpq -pncrv 192.168.123.89
remote refid st t when poll reach delay offset jitter
==============================================================================
*200.156.12.14 .GPS. 1 u 219 1024 377 5.934 0.028 0.006
+178.20.4.68 .GPS. 1 u 215 1024 377 13.166 0.042 0.030
associd=0 status=06f4 leap_none, sync_ntp, 15 events, freq_mode,
version="ntpd [email protected] Wed May 8 21:55:29 UTC 2013 (1)",
processor="x86_64", system="Linux/3.0.101-0.47.71-default", leap=00,
stratum=2, precision=-20, rootdelay=5.934, rootdispersion=18.169,
peer=49695, refid=200.156.12.14,
reftime=e02063ef.71ec06c0 Tue, Feb 26 2019 19:18:39.445, poll=10,
clock=e02064ca.e2fc87a1 Tue, Feb 26 2019 19:22:18.886, state=4,
offset=0.042, frequency=6.834, jitter=0.011, noise=0.029,
2 Which servers are synchronizing
ntpq -n -c peer 192.168.123.89
remote refid st t when poll reach delay offset jitter
==============================================================================
*200.156.12.14 .GPS. 1 u 241 1024 377 5.934 0.028 0.006
+178.20.4.68 .GPS. 1 u 237 1024 377 13.166 0.042 0.030