[ntp:questions] The libntp resumee...
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Sep 5 12:17:46 UTC 2008
Kay Hayen wrote:
> thanks to all who replied. Unfortunately the moderation bit made all of my
> last replies expire and instead of reposting them, I choose to sum things up
> in a single post.
> 5. The NTP rules about how often to query a daemon. I have tried to read up
> about it, but only found general advice. Under the assumption that ntpd is
> not multithreaded querying it at the time it should respond to other servers
> is slightly unfortunate. I was thinking that the query is so fast that it
> doesn't matter. I will have to back it up with numbers. I presume we could
> query the local ntpd for its time in a loop and compare with local current
> time to get an idea if extra libntpq queries degrade it or not.
The "rules" about how often to query a daemon are not all that
complicated. The fact that there ARE rules is due to some history;
google for "Netgear Wisconsin" for the sordid details. For a "second
opinion" google for "DLink PHK".
Briefly, you use the defaults for MINPOLL and MAXPOLL. You may use the
"iburst" keyword in a server statement for fast startup. You may use
the "burst" keyword ONLY with the permission of the the server's owner.
99.99% of NTP installations will work very well using these rules". If
yours does not, ask here for help!
"burst" is intended for systems that make a dialup telephone connection
to a server three or four times a day.
"iburst" sends an initial burst of eight request packets at intervals of
two seconds. Thereafter, the server is polled at intervals between 64
and 1024 seconds; ntpd adjusts the poll interval within this range as
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