Re: Can I synchronise local time with some NTP-server?
[ I'm CC:'ing [EMAIL PROTECTED] so that he can add this as a How to get started document to the web site. ] On Wednesday, June 4, 2003, at 03:37 PM, Constantine wrote: Hello! I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? My server is located in the USA, in case one would like to suggest some good servers to synchronise with. :-) I don't think that read the man page is a very good answer. The man page doesn't explain things very well (if someone would like to submit what I write below to the maintainer, please do so). Step 0: Is it ntp or xntp? Some operating systems supply binaries with the x and sometimes without the x. This document uses options that should work for either. I'll always specify the command without the x. If you receive a command not found, try it with an x. Step 1: Pick your servers Find some public servers that you can sync with. Two is good enough. There is a complete list here: http://www.ntp.org (it's a link to http://www.eecis.udel.edu/~mills/ntp/servers.html;) These sites are kind enough to perform this service for you, you should follow any guidelines they request (asking permission first, donations, thank-you notes, whatever.) Let's suppose you've picked clock.example.org and timekeeper.sample.com. Those aren't real sites, but I'll use them as examples in the rest of this document. Step 2: Manually set the clock correctly just once Let's manually set the clock to the correct time just to start things off. When ntpd is running and finds your clock is wrong, it makes tiny little changes until the clock is right. This way applications don't get confused. However, on reboot, the clock may have lost a lot of time and since no applications are running yet, we can make a big timeleap to correct the clock. To do this, we use a different utility called ntpdate. It can't run at the same time as ntpd. We even give it the -b option so that it knows to leap forward or backwards in time to set the clock correctly. Here's the command that does this: ntpdate -b clock.example.org timekeeper.sample.com (NOTE: Substitute the 2 NTP servers that you'd like to sync with.) Try this once from the command line (as root) to make sure you're got it right. # ntpdate -b clock.example.org timekeeper.sample.com 5 Jun 08:50:18 ntpdate[23777]: step time server SOME_IP_ADDRESS offset -111.106949 sec This means that your clock was off by -111.106949 seconds, but now it's been brought up to date. The good news is that for an instant you were in sync. The bad news is that by the time you read this, your clock has drifted. Darn computers! Step 2: Set the clock correctly on every boot up On reboot, you want to tell the system to sync up quickly. While your machine was down the CPU gets bored and plays with the clock. Haven't you ever been in a clock store waiting for your mother to make her purchase and started setting the clocks to funny times? It's like that, only your mother has nothing to do with this (I'm sure she's a very nice person, you just don't appreciate her enough). Let's configure your system to run this command on boot up. Here's how to do this on various operating systems: FreeBSD: Simply add this line to the end of /etc/rc.conf: ntpdate_enable=YES ntpdate_flags=-b clock.example.org timekeeper.sample.com Solaris 9: This is done automatically if a properly configured /etc/inet/ntp.conf exists. (people can volunteer the easiest way to do this on their favorite OS) Step 3: Keep the clock in sync permanently and continuously. Having your clock set properly every time you boot is nice, if you reboot constantly. Of course, you could put that command in cron but we have a solution that is so much better you'll thank me in the morning. We'll run ntpd which will constantly keep your clock correct by making micro-adjustments all day long. Heck, ntpd is so smart that if you lose contact with all your NTP servers it will remember how bad your clock was and keep making adjustments based on past bad performance. Pretty cool, eh? The NTP documentation has volumes about the various features and entire books can be written about the theory of operation of NTP. It's really quite amazing how the system works so precisely, so accurately, does the right thing through outages, detects and avoids misconfigured servers, conserves bandwidth, and fixes problems that you don't yet realize you have. However, you don't care about that, you just want a simple configuration that works. Here's one: Create a configuration file. Different systems call it different things. FreeBSD 4.x: /etc/ntp.conf Solaris 9: /etc/inet/ntp.conf Put these 3 lines in your configuration file: driftfile /etc/ntp.drift server
Re: Can I synchronise local time with some NTP-server?
An HTML-formatted version can be found here: http://whatexit.org/tal/mywritings/starting-ntp.html ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Thu, Jun 05, 2003 at 09:55:39AM -0400, Tom Limoncelli wrote: [ I'm CC:'ing [EMAIL PROTECTED] so that he can add this as a How to get started document to the web site. ] On Wednesday, June 4, 2003, at 03:37 PM, Constantine wrote: Hello! I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? My server is located in the USA, in case one would like to suggest some good servers to synchronise with. :-) I don't think that read the man page is a very good answer. The man page doesn't explain things very well (if someone would like to submit what I write below to the maintainer, please do so). Hi, The man page are not meant for this, there scope is limmited to the command. Books and article are. In fact the FreeBSD handbook have a section about this. http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-ntp.html Alex P.S. Its a good article. :-) ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Thursday, June 5, 2003, at 01:11 PM, Alex de Kruijff wrote: The man page are not meant for this, there scope is limmited to the command. Books and article are. In fact the FreeBSD handbook have a section about this. Yet of all the email on this topic, nobody pointed out this most excellent article. Of the many problems with the man page system, this is one that has always been a torn in my side. I feel that man pages should have a getting started section, even if it only points to articles like the one you suggested. http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network- ntp.html P.S. Its a good article. :-) I agree. It's a shame that the first place that people turn for help (the man pages) doesn't refer to it. -tal ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Thu, Jun 05, 2003 at 02:27:13PM -0400, Tom Limoncelli wrote: On Thursday, June 5, 2003, at 01:11 PM, Alex de Kruijff wrote: The man page are not meant for this, there scope is limmited to the command. Books and article are. In fact the FreeBSD handbook have a section about this. Yet of all the email on this topic, nobody pointed out this most excellent article. I was wondering about that to. Its not that hard to find, since it has a link on the main page of the website. Of the many problems with the man page system, this is one that has always been a torn in my side. I feel that man pages should have a getting started section, even if it only points to articles like the one you suggested. There is usaly a refereal section at the end of the manual. It is a idee to included a URL there. This is not possible for non-systems (aka comming from the ports). http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network- ntp.html P.S. Its a good article. :-) I agree. It's a shame that the first place that people turn for help (the man pages) doesn't refer to it. I meant you article here. (This may not have bin clear). I find the link is also good. I don't agree on the the shame part. I find the documentation of FreeBSD excelent. The startging point, realy, is the website (www.freebsd.org) and from there one can come to lots of mailinglist, newsgroups, article, and the handbook. I use FreeBSD for these reasons. The handbook is the starting your looking for. I feel that in this case the starter of this tread knew what he wanted to do, but not knew what he needed. I feel that he never would have read one the manuals, because of that. This mailinglist is, amoung other questions, for questions like his. Alex ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On 6/4/03 at 3:37 PM Constantine wrote: ! | |I am running FreeBSD 4.8. How can I synchronise my clock with some NTP |server? The time on my server right now is 4 minutes fast, and I do not |like that... Can I set up a script that would automatically synchronise |the time with some available server? | |My server is located in the USA, in case one would like to suggest some |good servers to synchronise with. :-) = man ntp man ntpdate http://www.ntp.org - look for the secondary servers to sync with. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
Constantine wrote: Hello! I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? My server is located in the USA, in case one would like to suggest some good servers to synchronise with. :-) Cheers, Constantine. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED] For a good time check out man ntpd and then do a google search on ntpd servers that are public and that should get you to having a good time with your clock. And go from there. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On 6/4/03 at 3:44 PM MikeM wrote: |On 6/4/03 at 3:37 PM Constantine wrote: |! || ||I am running FreeBSD 4.8. How can I synchronise my clock with some NTP ||server? The time on my server right now is 4 minutes fast, and I do not ||like that... Can I set up a script that would automatically synchronise ||the time with some available server? || ||My server is located in the USA, in case one would like to suggest some ||good servers to synchronise with. :-) | = | |man ntp |man ntpdate | |http://www.ntp.org - look for the secondary servers to sync with. = man ntp should be man ntpd sorry for the typo ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Wednesday 04 June 2003 21:37, Constantine wrote: I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? I guess, You are also trying to setup ntpd, because you believe the manpage about retired ntpdate. But it seems ntpdate is not retired. Just setup a cronjob which polls an ntp server. I think, ntpd does not work until you get explicit permission from the ntp-admin (you can write an email). Martin ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Wed, 4 Jun 2003, Constantine wrote: I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? The easiest way to do this is from /stand/sysinstall/configure/networking/ntpdate, which will give you a list of servers to select from. Cheers, Viktor ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Can I synchronise local time with some NTP-server?
On Wed, Jun 04, 2003 at 03:37:11PM -0400, Constantine wrote: Hello! I am running FreeBSD 4.8. How can I synchronise my clock with some NTP server? The time on my server right now is 4 minutes fast, and I do not like that... Can I set up a script that would automatically synchronise the time with some available server? Add: xntpd_enable=YES xntpd_flags=-l /var/log/ntpd.log # with logging to /etc/rc.conf (this flag is different in 5.0 mind for anyone else that tries this on 5.0) and then configure ntpd in /etc/ntpd.conf: server ntp2a.mcc.ac.uk # choose a server near you obviously :) driftfile /etc/ntp.drift I think you might have to 'touch /etc/ntp.drift' initially - same with /var/log/ntpd.log. My server is located in the USA, in case one would like to suggest some good servers to synchronise with. :-) As mentioned above check the official ntpd site - or even just google for 'ntpd server usa'. Cheers, Jez ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
