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

Bill Unruh unruh at physics.ubc.ca
Thu Sep 11 18:25:55 UTC 2008


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)?
This is highly likely to be the case for a laptop for example, where the
connection with the local network is only brought up by the user after a
while, or on wakeup from a power outage when the net may be unstable or the
router be out when ntp comes up. 

If a server disappears in a running ntp, ntp keeps trying, backing off on
the poll interval after a while. But what does ntp do if on the first try
to a server, there is no response, or if the dns is down. Does it forever
scrub that server? (that seems to be what happnes-- if so why?) or does it
do the same thing as if the server disappears after a while (keep trying
with increasing poll intervals)?

I notice that there is a keyword dynamic which is not yet implimented but
which seems to imply the second option.

Also what happens to ntpd if it has no servers whatsoever, not even a local
one? Does it keep running, doing nothing, or does it exit?





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