Thomas Sprinkmeier wrote: > @feisty, > > If your DHCP server isn't providing NTP servers then DHCP should have nothing > to do with NTP. > "/etc/rcS.d/S40networking" should have the NIC's up and configured long > before "/etc/rc[2345].d/S23ntp" tries to start NTP. I see the bug on feisty with a fast local network and local dhcp server.
> > Does you modem do 'lazy connects'? > I'm wondering if the DNS queries from NTP are the first thing the modem > hears, causing it to connect. > If the modem takes too long to connect then the DNS queries will fail and NTP > won't start. > Could you add a few IP addresses (rather than FQDN's) to your ntp.conf file? > What does "ntpq -p" say? > > @Phillipp > "Would it hurt to restart ntp whenever a network interface comes up?" > Yes, but not much. > NTP builds up information on remote servers and local clock drift. This is > lost on restart, meaning NTP won't work as well as it could (i.e. it'll take > longer to sync, and even longer to tweak the local clock frequency). > Arguably this is not a big problem for most situations where all you want is > accuracy within a few seconds (in which case "ntpdate" may be a better choice > anyway). I don't think this is a problem: the local clock drift information is stored in /var/lib/ntp/ntp.drift, so it is not lost upon restart. The information about servers builds up fast, and in the meantime, ntp's application of the stored drift info to the local clock keeps it accurate to a fraction of a second. As of 2005, the advice was that ntp does need to be restarted: http://lists.ntp.isc.org/pipermail/questions/2005-August/006333.html As of a week ago, it seems that the underlying ntp problem may have been fixed: https://support.ntp.org/bugs/show_bug.cgi?id=51 (see the bottom of that bug report). Eric > > The polling interval NTP uses tends to increase as time goes on (it starts at > 2^6 seconds (roughly once a minute), I've seen it as high as 2^16 (roughly > every 18 hours)). > Re-starting NTP will mean a shorter polling interval and more load on the > servers (especially if you use "iburst"). > > I think the thinking behind the "exit 0" in "/etc/network/if-up.d/ntp" > is that, if your network address changes, it was probably DHCP that > changed it and DHCP should be responsible for re-starting NTP. > -- ntp is being brought up before network is ready, causing ntp to not resolve any ip or host names and it appears ntp does not recover https://bugs.launchpad.net/bugs/114505 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
