How to keep your clock on track.

Stormy Eyes · Posted: Wed Jan 14, 2004 12:06 pm Post subject: How to keep your clock on track.

I bet I'm not the only one who sometimes finds his computer's internal clock drifting, but Gentoo does have tools to solve this problem: ntp. NTP is the "Network Time Protocol", which allows hosts to connect to time servers and sync their clocks to that of the server.

The NTP tools can be obtained using portage from the net-misc/ collection:

agent_jdh · Veteran Joined: 08 Aug 2002 Posts: 1783 Location: Scotland

If you choose to go with ntpd (which is arguably the better solution, as it keeps your clock synched silently, i.e. no user intervention required), you need to do a bit more to get it working. You have to edit the file /etc/ntp.conf and add in what timeservers you want to use (I would select stratum 2 - secondary - servers at the foot of the link you provided). Mine looks like this -

nevynxxx · Posted: Wed Jan 14, 2004 12:44 pm Post subject:

Nice tip(s), now the next step, how would I set my router machine to be an ntp server for the local network? (not much point on small networks I know but on say a corporate network this could be useful)

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Stormy Eyes · Posted: Wed Jan 14, 2004 12:49 pm Post subject:

Stormy Eyes · Posted: Wed Jan 14, 2004 12:51 pm Post subject:

ILikePi · Posted: Wed Jan 14, 2004 1:08 pm Post subject:

David Mills, who is one of the primary maintainers of the software, maintains a nice list of public NTP servers. Home users should try to limit themselves to servers on the "stratum 2" list.

I setup xntpd on a university department subnet a few years ago. It basically involved choosing the servers and configuring the daemons on the three machines. xntpd had some security features in it that allowed you to say things like "allow clock updates only from these addresses" or "allow clock queries from etc..." it also had some sort of key exchange type thing that went on between the 3 local servers. i'm not sure if the particular ntp daemon you all are referencing has that sort of thing though. also, can't remember for sure...but the hardware clock may need to be in GMT. but once it's configured and running, it's all hands-off.
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Stormy Eyes · Posted: Wed Jan 14, 2004 1:13 pm Post subject:

agent_jdh · Veteran Joined: 08 Aug 2002 Posts: 1783 Location: Scotland

nevynxxx · Posted: Wed Jan 14, 2004 1:33 pm Post subject:

Thanks all, can't test if my box is being a server, but from what you said it should be. When I edited my /etc/ntp.conf it had a line

restrict <my routers external address> mask 255.255.255.0

I chancged it to my internal network so my conf now looks like;

keschrich · n00b Joined: 09 Apr 2002 Posts: 69 Location: Branford, CT

I've got my ntpd.conf all set up, and when I run '/etc/init.d/ntpd start' everything seems to work great. I have noticed one problem though: whenever I reboot my computer, ntpd.conf seems to be replaced with this:

agent_jdh · Veteran Joined: 08 Aug 2002 Posts: 1783 Location: Scotland

jetblack · Posted: Wed Jan 14, 2004 2:50 pm Post subject:

ILikePi · Posted: Wed Jan 14, 2004 10:53 pm Post subject:

NME · Posted: Wed Jan 14, 2004 11:05 pm Post subject:

nice howto, thanks a lot

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k12linux · n00b Joined: 17 Oct 2003 Posts: 18

k12linux · n00b Joined: 17 Oct 2003 Posts: 18

Cid · Posted: Thu Mar 25, 2004 2:43 pm Post subject:

i'm having a little trouble getting this to work...here's the error:

# /etc/init.d/ntp-client start
* Setting clock via the ntp client 'ntpdate'...
25 Mar 09:31:38 ntpdate[4695]: the NTP socket is in use, exiting
* Failed to set clock [ !! ]

any suggestions?
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k12linux · n00b Joined: 17 Oct 2003 Posts: 18

neenee · Veteran Joined: 20 Jul 2003 Posts: 1786

hm.. what about a cronjob calling rdate?

k12linux · n00b Joined: 17 Oct 2003 Posts: 18

neenee · Veteran Joined: 20 Jul 2003 Posts: 1786

okidoki. i just thought ntp for a normal
user system to be a bit overkill :wink:

k12linux · n00b Joined: 17 Oct 2003 Posts: 18

Yeah, really it is overkill if all you want to do is keep your time from being way off "real" time. I run NTP on my home network because I want several systems to sync to it. If I only had a single (or a couple) PCs I'd probably just use ntpdate by itself.

And of course at work I use it because there it actually matters that I have a local accurate time source.

szaman · Posted: Thu Mar 25, 2004 9:21 pm Post subject:

is it possible to sync wind*ws systems to my ntp servers?

BlauwVoet · n00b Joined: 11 Feb 2004 Posts: 30

ntp seemed to complicated and too big (small HD) for me.
besides, I'm not interested knowing the time with a precision of nanoseconds.
something small, simple and fast is what I need

my linux-clock seems to work fine, so as long as my pc is switched on, everything runs smoothly.
my hardware-clock on the contrary is waaaaaaaaaaaay off; so every time I boot I have to adjust the time. (afraid the MoBo battery might fail pretty soon?) So I wanted to have something to do that automatically.

the ntp-ebuild is quite big, has several dependencies, seems to be quite complicated and to heavy for this simple task. So I tried clockspeed, only 25 kB.

Andersson · Posted: Thu Mar 25, 2004 10:04 pm Post subject: