Linux – NTP is running, Clock not synced. Manual DOES work

linuxntptime-synchronization

An ubuntu server is running ntp, and connected to the internet. Still, the system clock is about 30 minutes wrong and gets bigger over time.

$ service ntp status
NTP server is running..

Output of ntpq -p

remote           refid      st t when poll reach   delay   offset  jitter

mail.thefrown.n .INIT.          16 u    - 1024    0    0.000    0.000   0.000
193.1.12.167    .INIT.          16 u    - 1024    0    0.000    0.000   0.000
tshirt.heanet.i .INIT.          16 u    - 1024    0    0.000    0.000   0.000
chilipepper.can .INIT.          16 u    - 1024    0    0.000    0.000   0.000

Which makes it look like a firewall issue? Funny thing is, When I stop ntp and run the following command

ntpdate -u 0.europe.pool.ntp.org
14 Jul 09:27:40 ntpdate[3664]: step time server 217.198.219.102 offset -21.831200 sec

The time DOES get adjusted, which would make me believe that it's not a firewall issue?

Best Answer

.INIT. refid actually means the remote is still in an initialized state and has not received packets or pulses yet. It could be network traffic not allowed such as a firewall, but not necessarily.

30 minutes offset is beyond ntpd panic threshold. (Did you mean seconds? The offset in your ntpdate output is only tens of seconds.) Depending on configuration, it may only step the clock once, or refuse and quit. Several operating systems instead call ntpdate first before ntpd.

As mlichvar mentioned, both ntpdate and ntpd may be selecting 123 as the source port.

In addition, ntpdate refuses to adjust when "the NTP socket is in use", which is another reason why ntpd needs to be stopped first. Which is a useful safety mechanism if you do not want the time to be stepped like on a database server.

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