North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: ntp config tech note
That's NTPv4 isn't it? I also prefer to use three peers vs. two. Always an odd number, greater than 1. Assumptions can't be made about the mathematics behind time, but in a reference model, odd numbers are better. [Not to be confused with network timing, although the same clocks are used to provide sources for "time" over different layer 1/2/3 protocols ] -M -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Tony Li Sent: Thursday, May 20, 2004 4:07 PM To: Randy Bush Cc: [email protected] Subject: Re: ntp config tech note One minor (operational! -- gasp) addition: More modern copies of ntpd have a '-g' option that will allow the clock to jump once at boot time. Tony On May 20, 2004, at 12:27 PM, Randy Bush wrote: > > sorry to take you away from discussing spam with an actual > tech note, but twice this morning i have hit incidents where > much needed ntp clients were blown. so, as i was gonna have > to write it up, i figured i would bore you all with it. > > --- > > ntp config hint > 2004.05.20 > > ntpd will not work if your clock is off my a few minutes. > it just sits there forever with its finger in its ear. so, > > at boot, before you start ntpd, use ntpdate to whack your > system's time from a friendly low-numbered strat chimer. > > do not background ntpdate with -b, because, if it is slow to > complete, ntpd can't get the port when you try to start it > next in the boot sequence. > > if ntpdate takes a minute and thus adds to your boot time, > then something is wrong anyway; fix it. > > in case your dns resolver is slow, servers are in trouble, > etc. have an entry for your ntpdate chimer in /etc/hosts. > yes, i too hate /etc/hosts; but i have been bitten without > this hack; named is even more fragile than ntpd. > > once ntpdate has run, then and only then, start your ntpd. > and read all the usual advice on configuration, selection > and solicitation of chimers with which to peer, ... > > and then, if having accurate time on this host is critical, > cron a script which runs `ntpq -c peers` and pipes it to a > hack which looks to be sure that one of the chimers has a > splat in front of it. run this script hourly, and scream > bloody hell via email if it finds problems. > > --- > > now back to your regular spam discussion. /* > > yes, spam is an important issue. but, if your local > organization, this mailing list, ... gets swamped with > discussions of spam, then the spammers have won. > > you have to compartmentalize it, in your organization and > in the general net culture. that's why there are > separate mailing lists for spam, ddos, and other net crap > with which we have to deal. > > that's why we have more than one mailing list in the > world, to compartmentalize so we can focus. > > */ > > randy >
|