NTP question

[Ferdie Castro]

Hi I tried to command ntpq -p in my server A which is using ntp whose ntp server is server B.

Where can I see how many delay in secs/msecs is my time to server B? Am i right that the
one with * (asterisk) is the server I am syncing with using ntpq command. thanks

[Elmar P. Kolkman · Accepted solution]

The line with the '*' is the server you are syncing to.
In the 'offset' collumn you see the number of miliseconds you are off to the corresponding time server.

[Ferdie Castro]

Thanks. But for the offset. Sorry but I can't get what you mean. What do you mean I am off to the server? Is it the delay I was referring to. I tried to do date -u simultaneously server B 13:33:44 server A 13:34:20 and offset from server A is -0.003. What does -0.003 mean? is it possible for me to get the delay?

[Brian Bergstrand]

.0003 means that your clock is 3 milliseconds off from the ntp server. If you want the network delay, I believe that is listed in the "delay" column of ntpq's output.

HTH.

[Stuart Abramson_2]

offset is how different you are from the NTP server. Usually measured in milliseconds, I think.

A better question is "what is dispersion"? It has something to do with LAN delay.

# ntpq -p
remote refid st t when poll reach delay offset disp(ersion)
==============================================================================
*wcciss001.wcc.w ntp1.conectiv.c 2 u 342 512 377 1.11 8.430 4.68

[Ferdie Castro]

I want to be cleared by offset parameter in ntpq. No question that offset is in time unit (milliseconds). What does I am -0.003 off to ntp server mean? Is it I am my date/time is delayed/advanced 3 msecs from ntp server. Sorry guys I don't easily get what you mean.

[Elmar P. Kolkman]

It depends on the version of ntpq you are using. According to the man page of ntpq on some HPUX 11 server with the default xntp installation, the offset is in seconds, so it would mean you are 3 msec off of the time of the server. This is with a correction for the delay!

[Brian Bergstrand]

The delay is the round trip network time for an NTP packet from the client to the server or vice-versa. The offset is the amount of time your client is off from the ntp server. Both are displayed in seconds, so -.0003 seconds means that your client clock is 3 milliseconds short of the ntp server's clock.

A delay of .00098 would mean that it takes 9.8 milliseconds for a sync to take place.

HTH.

[Sanjay_6]

Hi Ferdie,

Try this for all the info you want on NTP.

http://www.ntp.org/

http://www.ntp.org/ntpfaq/NTP-a-faq.htm#S-META

Also on the server do "man ntpq" to understand the results of ntpq -p

Hope this helps.

Regds

[Brian Bergstrand]

Sorry, ntpq displays time in milliseconds, not seconds. xntpdc displays it's stats in seconds. I'm not sure what ntpdate uses, but I would guess seconds. So your clock would still be 3 milliseconds short.