Date: Wed, 17 May 2000 15:55:02 +0100 (BST) From: jpmg@eng.cam.ac.uk To: freebsd-questions@FreeBSD.ORG, james.wilde@tbv.se Subject: Re: xntpd setup Message-ID: <200005171455.1562@tulip.eng.cam.ac.uk>
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> I am setting up a machine to synchronize with an external ntp server (level > 2). I don't want to trouble them with too much traffic and assume that once > a day would be enough. The machine would then act as ntp server for the > company computers. > > I don't find any way to control how often the machine synchronizes with the > external server. How is this kind of behaviour normally set up? I can see > the possibility of a cron job at, say, 01:00 every day to contact the > external server, storing the pid in some file, killing the job, say 5 > minutes later and starting another cron job for internal broadcasting. This > job would then get killed at, say, 00:55 the next morning. Arrgggh. This really would break the way ntpd would like to work. ntp daemons work best when allowed to build up a knowledge of the state of the machine and their connections to other peers and servers over a nice long period of time. Even with the default settings, ntpd very quickly settles down to only pestering its servers every 1024 seconds, which corresponds to very little bandwidth or loading. If you _really_ want to minimise your impact on the machine providing the next stratum server, then you also have the option of setting the maxpoll for that server to 17 instead of the default of 10 (which means that instead of 2^10 == 1024 seconds, the maximum polling interval it will up itself to will be 2^17 seconds (or 36.4 hours). Something like server theirhost maxpoll 17 in your ntp.conf file (look at the man page for ntp.conf for more details) should do the trick. -patrick. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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