On Tue, 15 Feb 2000, Patrick Dahiroc wrote: >already on Feb 15, 2000. digging through the package database i came across >ntp and ntpdate and installed both (i have an always on connection to the
ntpdate is used to do a "one time only" update to your clock. ntp is used to discipline your clock and will in fact keep the RTC in a short leash updating it every 11 minutes. If you're going to use ntp (not ntpdate), remember to get rid of that systohc adjust crap in runlevel 6 (/etc/rc6.d, /etc/init.d; I forgot the script name, I think a search for systohc --adjust will find it). It does not play well with ntp most of the time. If you use ntp, you must use ntpdate as well. Ntp will refuse to run if your clock is off by more than a certain amount of time (which isn't very big BTW, so this is a real risk). ntpdate is used to 'force' the clock to an acceptable value at boot time, and after that you can either leave the RTC alone or use ntp to keep it synced. Ntp *requires* a reliable, fast, permanent internet connection for at least four or five hours a day to work properly AFAIK (but it really wants 24/7 connections), as well as a good configuration and nearby stratum2 time servers (it will work otherwise, yes. But not properly and you'd be better off with only ntpdate). If you don't have such a connection, restrain yourself to ntpdate. If you use modems for dialup, forget ntp and use ntpdate. If you don't have the time to read http://www.ntp.org/ and the docs in the package ntp-doc (which you didn't read or you'd not be asking the ML), and search the stratum *2* servers list for at least 2 near you (ping < 300ms is a must. <100ms is desired), request permission to use them (ntp will keep hammering them every 64-1024s, unlike ntpdate which does it only once), and deal with the hassle, you'd be better off with only ntpdate. > specify a server to ask. is there a list of machine that listens for ntpdate > connection? where? do i need to get permission (something to do with auth There's a list in http://www.ntp.org. You want the stratum ->**2**<- servers, not the Stratum 1 servers. >stuff) to ask those machines for the time? If you're using ntp, then YES, you must request permission to use the server about 4 times out of 5. If you're using ntpdate you should ask first, but since ntpdate only connects to the server when you run it (i.e.: once on every reboot, most people add a cron job for once a day as well) you might get away without asking permission. My advice is to stick to ntpdate, it is MUCH easier to config :-) -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
