[ntp:questions] converting from LOCAL clock to orphan mode

Nathan Stratton Treadway nathanst+ntp-questions at ontko.com
Fri Mar 23 22:21:24 UTC 2012

For some years now we've been running a time server for our office LAN,
configured with the LOCAL clock driver to allow our internal ntp client
machines to continue to synchronize with that server if it looses contact
with the outside world.

We're now in the process of configuring a new machine to take over this
role, and as part of the update I'd like to take advantage of
newly-available NTP features, including switching to using orphan mode. 
I've read through the orphan.html page in the NTP documentation and
related pages, but the examples described there are for a setup a bit
more complicated than ours, so I wanted to be sure I wasn't missing
anything important related to orphan mode in my new configuration.

In summary, I'm wondering if replacing this old config file:

  ["server" lines for some public internet stratum 1 servers]
  fudge stratum 10


  [same "server" lines]
  tos orphan 10

will in face result in the new server working essentially the same as
the old one did (as far as what the client of this server see when it
loses connectivity to its upstream servers)?

Also, does orphan mode actually offer any specific benefit over the
LOCAL clock in this case (i.e. when there is only one ntp server found
within the time island)?

A few additional notes on our setup, in case any are significant:

  * the old server is running ntp 4.2.2.p4, the new 4.2.6.p3 (Ubuntu

  * we just have the one local time server; all our client machines
    reference it with a "server ntp.ontko.com iburst" line in their
    ntp.conf files.

  * we have just one internet link out of our building; that link has
    been the most frequent point of failure (as opposed to the time
    server itself) over the years (but has been stable enough for our

  * the goal is simply to keep all the machines on our LAN close
    together, time-wise, if we loose our network connection to the
    upstream servers.



Nathan Stratton Treadway  -  nathanst at ontko.com  -  Mid-Atlantic region
Ray Ontko & Co.  -  Software consulting services  -   http://www.ontko.com/
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