ntp problems
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From: David Schwartz on 19 Apr 2010 18:20 On Apr 19, 9:05 am, "Bonno Bloksma" <bblok...(a)xs4all.nl> wrote: > If I have other hardware that only understands RFC868, can I service them as well, is there a > converter available I can install on my Debian Lenny servers? I don't specifically know Debian Lenny, but whatever inetd-equivalent is supplied on that platform should have that capability. If you have xinetd, follow this process: 1) Make sure no xinetd services are enabled that you don't want enabled. Check each file in '/etc/xinetd.d'. (Only needed if xinetd is not running already.) 2) Edit 'time-dgram' and 'time-stream' to enable these services and, if desired, restrict them. 3) If needed, start xinetd and configure it to self-start on reboots. DS
From: unruh on 19 Apr 2010 18:44 On 2010-04-19, David Schwartz <davids(a)webmaster.com> wrote: > On Apr 19, 9:05?am, "Bonno Bloksma" <bblok...(a)xs4all.nl> wrote: > >> If I have other hardware that only understands RFC868, can I service them as well, is there a >> converter available I can install on my Debian Lenny servers? > > I don't specifically know Debian Lenny, but whatever inetd-equivalent > is supplied on that platform should have that capability. If you have > xinetd, follow this process: > > 1) Make sure no xinetd services are enabled that you don't want > enabled. Check each file in '/etc/xinetd.d'. (Only needed if xinetd is > not running already.) > > 2) Edit 'time-dgram' and 'time-stream' to enable these services and, > if desired, restrict them. IF all you want is time to withing 10s to 100s of ms, then this will work, sort of ( results in a sawtooth behaviour of your clock). If you want better accuracy and a clock that runs at the correct rate to PPM, then use the ntp process to set your clock (ntpd, chrony,...) The time protocol is an ancient protocol which has been supersceded by ntp. > > 3) If needed, start xinetd and configure it to self-start on reboots. > > DS
From: David Schwartz on 19 Apr 2010 19:04 On Apr 19, 3:44 pm, unruh <un...(a)wormhole.physics.ubc.ca> wrote: > If all you want is time to withing 10s to 100s of ms, then this will > work, sort of ( results in a sawtooth behaviour of your clock). If you > want better accuracy and a clock that runs at the correct rate to PPM, > then use the ntp process to set your clock (ntpd, chrony,...) > The time protocol is an ancient protocol which has been supersceded by > ntp. Worst of all, if your hardware clock is fast, setting the clock using rdate may result in repeated backwards jumps in wall clock time. I should have pointed out that a much better solution is to relegate RFC868 to the dustbin of history. DS
From: Sidney Lambe on 19 Apr 2010 20:26 On comp.os.linux.networking, David Schwartz <davids(a)webmaster.com> wrote: > On Apr 19, 8:24=A0am, "Bonno Bloksma" <bblok...(a)xs4all.nl> > wrote: > >> Can I assume rdate is a proper ntp client? > > No, rdate is an RFC868 time client with no relationship > whatsoever to ntp. Use 'ntpdate'. > >> And if rdate -p 127.0.0.1 fails that there is a problem? > > It would be surprising if it succeeded since most Linux boxes > stopped supporting that protocol around the same time they > stopped running 'inetd' by default. > > DS You are mistaken. It comes with the latest Debian, for starters: http://packages.debian.org/lenny/rdate (This will work just fine on any distro. Is a simple utility needing only the basic libs to function.) For the newbies: ar x whatever.deb will give you three files. You only want data.tar.gz. Put it in / and run: tar xvzf data.tar.gz and it will install itself. I have been using rdate, running from a cron job, for years, with no problem at all. Why hassle with a complex app like NTP for such a simple task? For the OP: Just go to: http://support.ntp.org/bin/view/Servers/StratumTwoTimeServers And find a nearby time server. There are at least two versions of rdate around. The one I use requires the -s option to actually set the time. -p just displays the time given by the remote timeserver. The newer version of rdate supports both RFC 868 and 2030. And alternate ports. Sid
From: David Schwartz on 19 Apr 2010 21:29
On Apr 19, 5:26 pm, Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: > >> And if rdate -p 127.0.0.1 fails that there is a problem? > > It would be surprising if it succeeded since most Linux boxes > > stopped supporting that protocol around the same time they > > stopped running 'inetd' by default. > You are mistaken. It comes with the latest Debian, for starters: > > http://packages.debian.org/lenny/rdate > > (This will work just fine on any distro. Is a simple utility > needing only the basic libs to function.) Even if you have 'rdate', 'rdate -p 127.0.0.1' will fail if you're not running the 'rdate' server. When most distributions stopped enabling 'inetd' by default, they generally also stopped providing 'rdate' service by default. This applies whether or not you have a client or server installed. > I have been using rdate, running from a cron job, for years, with > no problem at all. You're getting sucky performance and risking a number of known problems. > Why hassle with a complex app like NTP for such a simple > task? Clock synchronization is not simple. It's very simple to do a mediocre job of it though. DS |