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Time Synchronization

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problem about time synchronization between 8 computers?

Newsgroups: comp.os.linux,comp.os.linux.networking,comp.os.linux.security

> learn ntpd. it's not that hard...

I would suggest xntpd though, I think that theprocess goes something like this:

su
ntsysv

— check to make sure neither ntpd nor xntpd are running, if they are then do a 'ps aux | grep ntp' and kill the processes

timconfig

— make sure you are set to GMT and your zone is correct

vi /etc/ntp.conf

you'll want to put an instance of the following, nore won't hurt, but it's not necessary:

server <server IP>

then a couple of these:

peer <server IP>
peer <server IP>

that will allow you to 'triangualte' your virtual position.

you put a:

driftfile <location of driftfile>

if you want to log your connections.

then an

authenticate no

should round out the file. (I usually don't authenticate, you can if you're really protective of your time though)

then run 'ntpdate <server>' or something like that to get your computer's clock set.

then I think that it is 'hwclock —utc —systohc' to set your computer's hardware time to the same as the computer's virtual time.

then you shoudl be able to

/etc/init.d/xntpd start

to get everythign running.

That's all off the top of my head, but it should at least set you in the right direction.

AngryBob

use cmd:cron

the rdate daemon is a default part of the Red Hat install.

Get one computer accurate (by NTP or rdate to the US naval observatory or some such) and then have each other machine call the "master." Put the following in each "slave" machines crontab:

10 11,23 * * * rdate -s dragon # accurate master machine
12 11,23 * * * hwclock --systohc # make it permanent

clock -w

Note that the clock command should be more than a minute after the rdate in case the rdate advances the clock by more than a minute; a minute is the most imaginable clock drift in a twelve hour period.

The "master_machine" entry should be the NTP or rdate host on your local network.

Cheers,

Russ Bixby, geek at large

use cmd:cron

rdate under solaris is just rdate hostname. But the rdate command under linux should be rdate -s (to set the time rather than just display it)

root@iitrc:~# crontab -l
[...]
# sync time with dragon
12 11,23 * * * rdate dragon

use cmd:cron

> Is there a list of definitive ntp servers on the internet?

See: http://www.eecis.udel.edu/~ntp[]

Nollaig MacKenzie

documented on: 2000.10.30 Mon 19:00:38