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Re: discovering whether the time on a host is correct (and being updated)
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Re: discovering whether the time on a host is correct (and being updated)


  • Subject: Re: discovering whether the time on a host is correct (and being updated)
  • From: Ben Artin <email@hidden>
  • Date: Thu, 29 Nov 2007 16:55:22 -0500

I have discovered that I can run "ntpq -p" on a command line and I may get an outcome similar to this:

[imacg5:~] chris% ntpq -p
remote refid st t when poll reach delay offset jitter
= = = = = = = = ======================================================================
time2.apple.com a17-106-100-13. 2 u 1563 68m 1 89.775 -0.729 0.008
[imacg5:~] chris%


On my machine, I do not seem to have the '*' in the first column indicating "happiness" on the part of ntpq. A Unix box at work, being fed by GPS and other peers, always has a * next to one of the entries. man ntpq indicates that ' ' in first column means, and I quote:

space (reject) The peer is discarded as unreachable, synchronized to this server (synch loop) or
outrageous synchronization distance.


Questions:
1) Should I expect a * if all is well and time is synched properly?

Yes.

2) Is this as good a way as any to determine whether a host machine is legitimately holding the right time?

The really depends on what you mean by "the right time". Knowing that machine is synchronized to some time server that you do not control does not really tell you much at all.


You should explain what you are trying to accomplish. What is the motivation for needing to be tightly synchronized?

3) What might I do on my own machine to achieve '*' status? ;-)

Fix whatever caused time2.apple.com to be unreachable 1563 seconds prior to when you ran that command? I believe that your ntpq output indicates that your machine is having problems talking to time2.apple.com. A firewall or a local network problem could cause that, as could an outage of time2.apple.com.


--

<http://artins.org/ben>

A: Because it reverses the logical flow of conversation.
Q: Why is top posting frowned upon?


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References: 
 >discovering whether the time on a host is correct (and being updated) (From: Chris Heimark <email@hidden>)

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