Date: Thu, 1 Oct 1998 10:24:08 -0500 From: Dan Nelson <dnelson@emsphone.com> To: "Andy.Robb" <Robb.Andy@x-tension.com>, "'freebsd-questions@FreeBSD.ORG'" <freebsd-questions@FreeBSD.ORG> Subject: Re: training timeofday clock with ntpdate Message-ID: <19981001102408.A8315@emsphone.com> In-Reply-To: <B766A4A0DB0BD2119BF40000F824778EE42F@mailhost.x-tension.co.uk>; from "Andy.Robb" on Thu Oct 1 11:51:51 GMT 1998 References: <B766A4A0DB0BD2119BF40000F824778EE42F@mailhost.x-tension.co.uk>
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In the last episode (Oct 01), Andy.Robb said: > I understand that the kernel includes code to trim the clock > frequency when using xntpd. However, xntpd raises the ISDN line to > our ISP every few minutes. Are you using user-ppp or pppd for your ISDN link? Both have a filter feature where you can specify exactly which packets trigger a dialout. In pppd, it's called "active-filter". In ppp, it's called "dfilter" and "afilter". If you tell ppp to not dial out on UDP port 123 packets, you can leave xntpd running all the time. It will sync when the line is up, and will do its best when the line is down. Configure xntp to use hardware clock at a low stratum (say 10 or so): server server.onthe.inter.net server 127.127.1.0 fudge 127.127.1.0 stratum 10 driftfile /etc/ntp.drift So when you are offline, xntpd will use the hardware clock (adjusted for drift). When you are online, it will resync to a more accurate time source. The NTP faq at http://www.eecis.udel.edu/~ntp/ has a lot of articles on this exact topic, but they all boil down to what I just said above :) -Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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