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

Harlan Stenn stenn at ntp.org
Fri Sep 12 19:03:21 UTC 2008

>>> 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?

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

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