[ntp:questions] Re: Using a local clock on an isolated subnet

Dale Worley worley at dragon.ariadne.com
Mon Aug 11 15:37:17 UTC 2003


Janet Dueck <janet at sfu.ca> writes:
> 	I have set up a server to use it's local clock so that it can act
> as a time source on an isolated network.  The local clock appears to be
> syncing the server but isn't being used for any external queries.  When I 
> try to update using the server I get an error "no server suitable for
> synchronization found".  I have very little experience with NTP - what
> do I need to do so that the local clock can be used for external queries?

First, do "ntpq -p 192.168.109.41", so we can see the state of the
server in question.  If it doesn't consider itself synchronized (for
any of a number of reasons), then ntpdate will refuse to use it as a
source.

> /etc/ntp.conf on the server (192.168.109.41)
> 
> # Drift file
> driftfile /etc/ntp/ntp.drift
> #
> # time servers for this host
> #
> server 127.127.1.1 prefer               # LCL, local clock
> fudge  127.127.1.1 stratum 0 refid LCL  # increase stratum

This is not the thing to do.  I don't know if "stratum 0" is even
valid.  But in any case, you should use something like "stratum 10",
so that any NTP which ultimately gets its time from this local clock
has a high stratum, and so an observer will recognize that the time
probably does not come from a reference maintained by a timekeeping
organization.

Dale



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