i have installed Linux Centos 7 in vmware workstation. i also have installed Quagga routing suite in centos and configured it to communicate with cisco Routers in GNS3 which is installed in Host (windows 10).

i have configured one of my routers in GNS3 as ntp server and they are all synced. now i want my centos to be synced with the others. to do that, i have installed ntpd and configured it as bellow :

server iburst is my cisco router that acting as ntp server and also it is reachable from centos. but my centos time is not synced. this is the output when i enter "ntpstat" in centos command line :

ntpstat output

as you see it says it is unsynchonised. this is the output of "ntpq -p" :

ntpq -p output

as you see it lists the server but the jitter is very high. i want to mention that i also have disabled vmware time synchronization with host through vmware tools. but still no result and time not synced. any help would be appreciated.

1 Answer 1


Your offset is nearly 58,000 ms and will take a very long time to adjust via slew. It will be faster to shut down ntpd, adjust the clock by a minute, and start ntpd back up.

This is an emulated router lab in GNS3? You will have better timekeeping performance by specifying local or Internet ntp peers. Unless perhaps NTP configuration is part of the exercise.

ntpstat unsyncronized means that the leap indicator status code reports never synchronized. Let it run for an hour or so, after it has exchanged many more NTP packets and adjusted the clock, and check it again.

  • i changed my ntpd configuration and instead of specifying the cisco router as ntp server, i entered the following NTP server located in internet in my ntpd config file : server 0.us.pool.ntp.org iburst. but it is still unsynchronized and ntp jitter and offset are 673 and 1666 accordingly. it just does not get synchronized anyway. is it something wrong with vmware workstation? i mean if i install a centos server on a physical machine(not VM), will ntp work right?
    – majid67110
    Feb 14, 2017 at 14:16

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