Re: Clock synchronization from dialup?
It seems to me that if you put a line like this in your /etc/network/interfaces in the section associated with your PPP connection you could sync your system time whenever you brought the interface up: up /etc/init.d/ntpdate restart || true This does not address the issue of having that system also serve NTP to your other machines, which might get interesting if your server is frequently out of touch with the outside world... * To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *
Re: Clock synchronization from dialup?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 At some point hitherto, Mark Polhamus hath spake thusly: > Has anyone come across clear, concise instructions for synchronizing > my clock to a network time server? I need instructions that will > work for a system that connects to the internet using dial-up (i.e. > is often NOT connected). It is never connected to the internet at > startup, and is restarted frequently. This scenario makes maintaining synchronization difficult. ntpd seems to expect that you will be connected permanently, and in my experience if it can't contact its time servers for some period of time, it will die. You could keep the clock mostly pretty up-to-date by using ntpdate in your connection script, and then using the hwclock command to set the hardware clock to the new time. You could also do this in a script run periodically by cron. In that case, the synchronization would fail whenever you're not connected, but as long as the machine is up and connected so that it runs successfully once or twice a day, your clock should be kept pretty accurate. > I assume ntp will do this for me if I configure it correctly, and I > would prefer to use ntp because I have virtual machines that I would > like to synchronize to the host machine. I assume you mean something like VMWare running on the same machine? If you should happen to have other machines on your network which are always connected to the Internet somehow, then a much better option would be for you to run ntpd on one of those hosts, and synchronize against that. May not be an option for you though. - -- Derek Martin [EMAIL PROTECTED] - - I prefer mail encrypted with PGP/GPG! GnuPG Key ID: 0x81CFE75D Retrieve my public key at http://pgp.mit.edu Learn more about it at http://www.gnupg.org -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9MZiudjdlQoHP510RAiYuAJ0YILCv9ydTDzov4Tu79pm8ejyl1ACgnZA3 fqtbZgUiZQqOmeOCGI/8c9A= =6yvo -END PGP SIGNATURE- * To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *
Re: Clock synchronization from dialup?
Although I am on 24x7, ntp can be used for dialup. These are the two lines I added. server 158.121.104.4 # timeserver.cs.umb.edu server 140.239.10.5 # ntp.ourconcord.net However, you might just want to use ntpdate. ntp runs as a daemon where ntpdate is not. You can write a cron script that tests if you are online. If so, execute ntpdate (as root) to synchronize your clock. Or you could set up a script around your PPP program to execute ntpdate when you log on. Mark Polhamus wrote: > Has anyone come across clear, concise instructions for synchronizing my clock > > to a network time server? I need instructions that will work for a system > that connects to the internet using dial-up (i.e. is often NOT connected). > It is never connected to the internet at startup, and is restarted frequently > . > > I assume ntp will do this for me if I configure it correctly, and I would > prefer to use ntp because I have virtual machines that I would like to > synchronize to the host machine. > > I'm having a hard time hacking through the thicket of ntp documentation -- it > > seems to be written for a someone who has a doctorate level interest in the > absolute limits of network time sync accuracy (even the "executive overview" > includes some equations!). There are a huge number of configuration options > for this package. > > Some example ntp.conf files would be nice. I would also appreciate > debugging/logging hints, and even an idea of how to tell if my setup is worki > ng. > > (ntp 4.1.1-1 on RedHat 7.3) > > Chrony also sounded promising, but it doesn't compile on 7.3: > > >gcc -Wmissing-prototypes -Wall -O2 -g -DLINUX -DHAS_SPINLOCK_H -c > wrap_adjtimex.c > >In file included from /usr/include/linux/timex.h:152, > > from wrap_adjtimex.c:40: > >/usr/include/asm/timex.h:10:21: asm/msr.h: No such file or directory > > > Thanks, > > > -- Mark Polhamus > -- [EMAIL PROTECTED] > > > * > To unsubscribe from this list, send mail to [EMAIL PROTECTED] > with the text 'unsubscribe gnhlug' in the message body. > * > -- Jerry Feldman <[EMAIL PROTECTED]> Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9 * To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *
