[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
list.

>> 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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