[ntp:questions] ntp client: keep all servers at startup

mayer at gis.net mayer at gis.net
Wed May 4 21:10:13 UTC 2005


----- Original Message Follows -----
> mayer at gis.net wrote:
> > ----- Original Message Follows -----
> > 
> >>You might consider configuring the server as a broadcast server, and
> >>the client as a broadcast client. That way the client will be
> >>listening for incoming packets at startup. If none arrive, or the
> >>server does not  respond, it should just stay in the listening mode.
> >>So if the server  isn't up/responding it should not affect the
> >>capability of the client to  aquire good time once the server is
> back >>online.
> >>
> > 
> > 
> > It will not show up in the list of associations until the server is
> > reachable, whether it's set up for broadcast or as a server. The
> > daemon will keep trying at regular intervals until it's available,
> > sets up the association and then looks to see where it fits within
> > the other associations that it has. Just because it doesn't show up
> > doesn't mean that it's not trying to reach it.
> > 
> > Danny
> > 
> 
> That's what I thought. But in a quick test it did not appear to be the
> case.
> 
> ntp.conf test
> # my DCF lashup
>   server 127.127.28.0 # use the shared memory reference clock driver.
> # two of the servers from ntp.org pool
> server enigma.wiredgoats.com maxpoll 12
> server mx2.gs.washington.edu maxpoll 12
> 
> pull the ether connection
> stop/start ntpd
> wait a bit (ntpdate times ot very slowly) and put back the ether
> cable:
> 
> run ntpq -p  in a 65sec cycle
> 
> Wed May  4 17:47:06 CEST 2005
>       remote    refid      st t when poll reach   delay   offset 
> jitter
> ======================================================================
> ======== *127.127.1.0 LOCAL(0)   10 l   41   64   17    0.000    0.000
>   0.001
>   127.127.28.0 .DCF.      0 l   42   64   13    0.000   -6.200   4.467
> ...........
>   Wed May  4 18:05:16 CEST 2005
>       remote           refid      st t when poll reach   delay  
> offset 
>   jitter
> ======================================================================
> ========
>   127.127.1.0  LOCAL(0)  10 l   35   64  377    0.000    0.000   0.001
> *127.127.28.0    .DCF.   0 l   35   64  177    0.000   -1.886  20.032
> 
>    So the two external servers don't get picked up (after  15mins)
> 

What did you expect? You gave them names and not IP addresses. Since the
DNS query fails it will never try to connect to them. The scenario that
I was talking about was when the ntpd daemon itself is down, not when
you
are unable to get the IP addresses. Try this with IP addresses instead
of names. I can tell you that it will keep retrying the address if it
has it. It won't do anything if it can't get the address.

Danny




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