[ntp:questions] Not able to connect

Richard B. Gilbert rgilbert88 at comcast.net
Thu Nov 16 23:10:26 UTC 2006


terrypearl wrote:

> Steve - I thank you for your time in replying. Hopefully I can get this 
> operational.
> 
<snip>
> 
>      remote           refid      st t when poll reach   delay   offset 
>  jitter
> ============================================================================== 
> 
>  192.245.169.15  .PPS.            1 u   76 1024    1  123.394  8246.05   
> 0.002
>  gatling.ikk.szt 195.111.99.186   2 u  105 1024    1  120.227  8239.82   
> 0.002
>  raptor.tera-byt 132.163.4.101    2 u   88 1024    1   87.253  8238.11   
> 0.002
>  time-a.nist.gov .ACTS.           1 u   87 1024    1  158.194  8318.57   
> 0.002
>  time-b.nist.gov .ACTS.           1 u   83 1024    1  125.022  8299.00   
> 0.002
> 
> which doesn't show a default with an asterisk which somebody said would 
> indicate the system used by ntpd to set the time automatically and keep 
> it synched. Is this true? How can I tell if ntpd is working and keeping 
> the clock synched?

You didn't wait nearly long enough between starting ntpd and running 
ntpq -p!!  The banner shows that each server has responded only once. 
The poll interval seems rather high to say the least.  Polling normally 
starts at 64 second intervals unless you tamper with the defaults for 
MINPOLL and MAXPOLL.  Such tampering is NOT a good idea!!!

Adding "iburst" to each of your server statements in ntp.conf should 
give you a much quicker startup.  It causes the first eight request 
packets to be sent at two second intervals and gets the information 
necessary to start synchronizing your clock in about sixteen seconds 
instead of almost six minutes.

When the number in the "reach" column reaches 377 you know that the 
server has responded to the last eight requests; it's an eight bit shift 
register and the display is in octal.  Each response from a server 
shifts a one bit in from the right hand side.  When a server fails to 
respond a zero is shifted in.

So make the necessary changes to ntp.conf and restart ntpd.  Wait four 
or five minutes and say "ntpq -p".   You should then get a banner that 
shows 377 for all the servers, and one of them should be marked with an 
asterisk in column one.  The asterisk indicates "selected as the 
synchronization source".  From zero to three others may be marked with a 
plus sign.  The plus sign indicates the server is a member of the 
"selection set" and is thus a candidate for selection as the 
synchronization source.  Minus signs indicate rejected servers and an 
"X" indicates that the server is considered "insane"!




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