[ntp:questions] What happens if ntp server unavailable at start up?

Unruh unruh-spam at physics.ubc.ca
Fri Sep 12 20:36:03 UTC 2008

Harlan Stenn <stenn at ntp.org> writes:

>>>> In article <s_tyk.1969$1x6.743 at edtnps82>, Unruh <unruh-spam at physics.ubc.ca> writes:

>Unruh> Steve Kostecke <kostecke at ntp.org> writes:
>>> On 2008-09-11, Bill Unruh <unruh at physics.ubc.ca> wrote:

>>>> A question has arisen in another group-- What happens if, when ntp
>>>> starts up, the remoter server is unavailable ( eg no DNS or no
>>>> connection)?

>I think, and I could be wrong:

>- if we can't reach DNS, we keep trying until we do
>- if we get an authoritiative "That site doesn't exist" we move on
>- if the interface is unavailable it will be added to the list when
>  it comes up.

>If we know the IP of the remote machine, it is added to the association

>>> As of 4.2.4p5 ntpd does the right thing in these situations. Here's an
>>> extract from the stable release ChangeLog:
>>> (4.2.4p5) 2008/08/17 Released by Harlan Stenn <stenn at ntp.org>
>>> * [Bug 841] Obsolete the "dynamic" keyword and make deferred binding to
>>> local interfaces the default.  Emit a warning if that keyword is used for
>>> configuration.

>Unruh> "deferred binding to local interfaces" means what? If my server is a
>Unruh> pool.ntp server, but my gateway is down when I boot up, will it
>Unruh> eventually bind to pool? Or just say-- the hell with it? What counts
>Unruh> as "local"?

>A local interface is a NIC on the local machine.

>There are a bunch of pieces here, DNS, NICs, and routing.

>Unruh> Did the dynamic keyword ever work? The web docs say that it is not
>Unruh> yet implimented.

>I'm pretty sure it works - what documentation says it doesn't?

Some document on ntp.org describing the options in the ntp.conf file. 
I do not want to look for it again-- the docs are incredibly hard to
search-- one of the  problems with making them into an infinite number of
web pages. So I guess dynamic went from not implimented to deprecated with
only a brief stop  of in use in between.

>Harlan Stenn <stenn at ntp.org>
>http://ntpforum.isc.org  - be a member!

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