Date: Wed, 19 Jan 2000 19:28:13 +0100 (CET) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-questions@FreeBSD.ORG Subject: Re: time sync problem--ntpdate AND xntpd?? Message-ID: <200001191828.TAA22610@dorifer.heim3.tu-clausthal.de> In-Reply-To: <864n5j$30mu$1@atlantis.rz.tu-clausthal.de>
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Sean Noonan <snoonan@cx952600-a.fed1.sdca.home.com> wrote in list.freebsd-questions: > [...] > Until I read this in man ntpdate: "Ntpdate will decline to set the date > if an NTP server (e.g. xntpd(8)) is running on the same host". > > So, what should I do? It didn't/doesn't make sense to me to have all of > my worksatations use internet bandwidth to check time; better to have one > check the time and the the rest get their time from it. > > What am I missing, conceptually? What are my alternatives? Is their a > NTP proxy I could run on my firewall? "ntpdate" sets the clock just once and then exits. "xntpd" is a daemon which runs in the background and corrects the clock continously. It synchronizes with one or more servers on the net every now and then (it doesn't take much bandwidth, so there is no reason to worry). It's even clever enough to calculate the drift of your local clock, so it can correct it even if there is no network connection for some time. However, "xntpd" only works if the clock is "about right" already. It refuses to touch the clock if the deviation is larger than 5 minutes, because in that case it thinks that something is seriously wrong. "xntpd" tries not to make "steps", but rather speeds the local clock up slightly or slows it down slightly, in order to correct for the drift. Therefore, you usually run _both_ "ntpdate" and "xntpd". First "ntpdate", in order to correct the clock once, no matter what. The you run "xntpd" in the background to keep the time in sync with the world. In FreeBSD, this is pretty easy to configure, just set ntpdate_enable and xntpd_enable both to "YES" in your /etc/rc.conf file (see /etc/defaults/rc.conf for the default values). Then you'll have to create an /etc/ntp.conf file (see the manpage for details) which contains the servers which you want to use for NTP. Note that "xntpd" can be used as a server and as a client, or both at the same time. That is, you can run xntpd in server+client mode on one box which syncs with some NTP servers out there on the net. Then you can run "xntpd" clients on other machines of yours to sync to your server. Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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