2004-11-26 Software

I started to read *The NTP FAQ and HOWTO: Understanding and using the Network Time Protocol (A first try on a non-technical Mini-HOWTO and FAQ on NTP)* ¹ because my computer clock is off by more than ten minutes, and I haven’t had that problem in ages. New hardware, no ntp installed (I think?)...

¹

As root, you can run *ntpdate pool.ntp.org* – or you can use certain subdomains like *europe* or (in my case) *ch*:

root@confusibombus:/etc# date; ntpdate ch.pool.ntp.org; date
Sat Nov 27 20:41:30 CET 2004
Looking for host ch.pool.ntp.org and service ntp
host found : armagnac.ifi.unizh.ch
27 Nov 20:41:30 ntpdate[1274]: step time server 130.60.75.72 offset -0.577247 sec
Sat Nov 27 20:41:30 CET 2004

So from time to time, I will just run the ntpdate command with a server on the command-line. Comments on 2004-11-26 Software also talks about the info in the _etc_ntp.conf file and how to use the ISP’s ntp server.

Comments on 2004-11-26 Software

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Comments

(Please contact me if you want to remove your comment.)

i’m still on 9.1:

$ slacklist.sh ntp
-rw-r--r--    1 root     root        12733 Oct 10 11:21 ntp-4.1.2-i486-2
~ $ cat ~/bin/ntpdate.sh
#! /bin/sh
echo `date`
sudo /usr/sbin/ntpdate -b -s 128.194.254.9
echo `date`

comments:

i used to have it set up to poll the ntp server every 12 hours, but that is overkill (i don’t like to overburden any resource).

now i just run the script every week or so, and see how much the clock has drifted since the last time i synced.

– GregScott 2004-11-26 22:52 UTC

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Hm. Specifying the server on the command line works.

I was trying to use the following _etc_ntp.conf file from the NTP wiki:

NTP wiki

server pool.ntp.org
server pool.ntp.org
server pool.ntp.org
server pool.ntp.org
restrict default noquery notrust nomodify
# restrict 127.0.0.1
# restrict 80.218.0.0 mask 255.255.248.0
# fudge 127.127.1.0 stratum 3
# server 127.127.1.0
driftfile /etc/ntp.drift
logfile /var/log/ntp.log

But it doesn’t work as expected:

root@confusibombus:/home/alex# ntpdate
27 Nov 09:37:25 ntpdate[1252]: no servers can be used, exiting

And furthermore:

root@confusibombus:/home/alex# ntpq -np
ntpq: read: Connection refused

On the command-line it works. Strange.

root@confusibombus:/home/alex# date; ntpdate ch.pool.ntp.org; date
Sat Nov 27 09:41:22 CET 2004
Looking for host ch.pool.ntp.org and service ntp
host found : gaia.ailab.ch
27 Nov 09:41:21 ntpdate[1274]: step time server 130.60.75.60 offset -1.305593 sec
Sat Nov 27 09:41:21 CET 2004

– Alex Schroeder 2004-11-27 08:42 UTC

Alex Schroeder

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not really related, except it’s an online clock, you might have allready seen it but anyway I like the idea:

http://www.humanclock.com/

Alex,

you might need a line in ntp.conf to remove the global “restrict” just for the server you want to use:

 restrict <server>

i long ago installed over my customized ntp.conf, but i think the logic is:

 restrict default ...blah blah
 restrict my_preferred_server

the first restrict blocks everything, the second is necessary to “unrestrict”. yes it is confusing if it works that way...

– GregScott 2004-11-27 18:04 UTC

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I notice that _etc_ntp.conf gets rewritten after every boot. I need to investigate. The answer was provided by clavius on ​#slackware @ freenode: It turns out that dhcpcd rewrites the config file:

restrict default noquery notrust nomodify
restrict 127.0.0.1
restrict 80.218.0.0 mask 255.255.248.0
fudge 127.127.1.0 stratum 3
server 127.127.1.0
driftfile /etc/ntp.drift
logfile /var/log/ntp.log

When I use whois 80.218.0.0, I get this:

inetnum:      80.218.0.0 - 80.218.0.255
netname:      CABLECOMMAIN-NET
descr:        Cablecom GmbH
descr:        DHCP Scopes
descr:        Zuerich

My provider! Aha! Trying:

root@confusibombus:/etc# ntpdate 80.218.0.1
Looking for host 80.218.0.1 and service ntp
host found : 80-218-0-1.dclient.hispeed.ch
27 Nov 21:44:01 ntpdate[1483]: adjust time server 80.218.0.1 offset 0.126001 sec

I guess that’s the correct usage of the ntpdate command.

– Alex Schroeder 2004-11-27 19:39 UTC

Alex Schroeder