Hi guys, I don't use virtual machine. The 192.168.0.191 is an internal ntpd server configured by administrator, so i can not see what ntp server it synchronizes to or what is its time reference. But i have added a new line "server 192.168.0.191" into file "/etc/ntp.conf" on ntpd client machines, and the output to execute command ntpstat is as follows: synchronised to NTP server (192.168.0.191) at stratum 3 time correct to within 80 ms polling server every 128 s Is it an proper way to synchronize clock?