Re: Problems with ntp, ntpdate and chrony
Hello Donald,
thank you for your answer!
Reading your mail I found the problems of my configuration :-)
> I am using this combo (ntpdate + ntp) on an Alpha XLT (Alcor) without
> any problems, although I am running "Testing" + 2.2.19 kernel here.
Now I have it working too!
> I checked my files, and they are almost identical to yours. The main
> differences are the actual external time-servers, and the ntpdate
> startup line in /etc/init.d/ntpdate is written a bit differently from
> yours...it calls a $NTPSERVERS variable stored in
> /etc/default/ntp-servers. Here is my line: " /usr/sbin/ntpdate -u -b
> -s $NTPSERVERS". Note that mine uses the option "-u". The
> /etc/ntp.conf file is identical to yours.
The -u options tells ntpdate to use an unprivileged port.
After using -u, ntpdate worked!
I read the man page one and the help to ntp once more:
The answers from the ntp daemons came on port 123/udp.
But my firewall did not let any packet in from ports
bellow 1024 :-)
> Dunno what could be giving you the problem, but here are some things I
> had to "learn" in order to get my setup working.
>
> 1. NTPDATE and NTP have different functions. NTPDATE is a "true"
> client that will sync your system clock to an external standard no
> matter how large the difference in times. NTP is more of a "server" in
> that will provide time-synch services to OTHER computers and will keep
> in synch with an external time source. Its method of synching to an
> external source is different and quite a bit slower. NTP makes use of
> the system clock's "drift". It is generally not too good if there are
> large differences between your system clock and the external time source
> and may take several hours/days to get in reasonable synch.
I do not stop my computer if not necessary; so I call ntpdate at startup
and than start the ntpd. The drift of the internal clock seens to be quite
big: about 400 sec in one week...
> 2. If you are NOT setting up a local "time-server" for your LAN, you
> really don't need NTP. NTPDATE will update a single system just fine.
> If your system has a LOT of drift, you can run NTPDATE periodically via
> a cron job. This is usually not necessary if you re-boot (run NTPDATE)
> daily. A lot of this will depend upon the time precision you require.
It is possible that I want to use it as a ntp server for my LAN in the
near future...
> 3. If you are setting up a local time-server, the usual method is to
> run NTPDATE first to get the system clock "in the ball-park", then start
> NTP and let it keep the synch. On my machine, NTPDATE is run first at
> startup in the /etc/rcS/ series of scripts, then NTP is started in the
> /etc/rc2.d/ (run-level 2) series of scripts.
Yes!
> 4. NTPDATE and NTP cannot be run at the same time! I would suggest
> concentrating on getting NTPDATE working before you add in NTP to the
> overall problem set.
So I did.
> 5. Some external time-servers used for synching are "private" and you
> may not have access to them. There is a good listing for these at
> http://www.eecis.udel.edu/~mills/ntp/servers.htm. I reviewed the
> listing for my area and selected Stratum-2 time-servers that were marked
> "public". In any case, it is good practice (courtesy) to let the
> sys-admin know you are using their time-server.
Thank you very much for this link, I found some good servers there!
> 6. I had a LOT of initial frustrations getting NTPDATE to work, before
> I finally determined that the external time-server I was trying to use
> was down! This is an obviouly simple thing, but I overlooked it for
> quite a while! Check it out with a ping to see if it is really there
> <g>. The IP numbers you used worked for me today...
> That is a complete data-dump from here. I wanted a local time-server
> for my home LAN, and set this up. Strangely, I had a great deal of
> problems getting this going on my IPMasq router (an i386 machine) but
> when I moved it to the Alpha, it started working immedialtely. I never
> figured that one out ... maybe something to do with the dual
> NICS...dunno! All the stuff I "learned" above was on the i386 machine.
> I have had absolutely NO problems with the setup on the Alpha.
>
> Sorry for the length....
>
> Cheers,
> -Don Spoon-
>
Once more, thank you very much for your complete answer!
Now will have a look at the systemtime tomorrow morning
so I will see if everything is alright!
Best regards,
Christoph
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