ntpd does not re-query servers, when a new interface appears

Tue Mar 9 13:30:49 UTC 2010

On Tue, Mar 09, 2010 at 02:17:48PM +0100, Dominic Fandrey wrote:
> On 09/03/2010 11:27, Ian Smith wrote:
> > On Tue, 9 Mar 2010, Dominic Fandrey wrote:
> >  > ntpd tracks interface updates, however it does not requery
> >  > servers, when they occur. This was less than an hour ago,
> >  > at my university, the notebook boots and is not connected
> >  > to anything:
> >  > 
> >  >  9 Mar 08:07:17 ntpd[1510]: logging to file /var/log/ntpd
> >  >  9 Mar 08:07:17 ntpd[1510]: precision = 2.234 usec
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #0 wildcard, 0.0.0.0#123 Disabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #1 wildcard, ::#123 Disabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #2 bge0, 192.168.1.12#123 Enabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #3 lo0, fe80::1#123 Enabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #4 lo0, ::1#123 Enabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on interface #5 lo0, 127.0.0.1#123 Enabled
> >  >  9 Mar 08:07:17 ntpd[1510]: Listening on routing socket on fd #26 for interface updates
> >  >  9 Mar 08:07:17 ntpd[1510]: kernel time sync status 2040
> >  >  9 Mar 08:07:17 ntpd[1510]: frequency initialized 3.155 PPM from /var/db/ntpd.drift
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: 0.de.pool.ntp.org
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `0.de.pool.ntp.org', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: 1.de.pool.ntp.org
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `1.de.pool.ntp.org', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: 2.de.pool.ntp.org
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `2.de.pool.ntp.org', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: ntp1.rz.uni-karlsruhe.de
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `ntp1.rz.uni-karlsruhe.de', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: ntp1.rz.uni-karlsruhe.de
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `ntp1.rz.uni-karlsruhe.de', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: ntp3.rz.uni-karlsruhe.de
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `ntp3.rz.uni-karlsruhe.de', giving up on it
> >  >  9 Mar 08:07:20 ntpd[1542]: host name not found: ntp4.rz.uni-karlsruhe.de
> >  >  9 Mar 08:07:20 ntpd[1542]: couldn't resolve `ntp4.rz.uni-karlsruhe.de', giving up on it
> >  > 
> >  > So ntpd has given up on all the servers listed in the ntp.conf file.
> > 
> > Yes, but it looks more like name service that's not operating, ntpd 
> > seems to be doing its best but can't resolve the hostnames?
> 
> Why would I have named running on a notebook? This is a notebook,
> which is not connected to the internet.
> 
> >  > I then proceed to connect to the wireless network and proceed to log
> >  > into two VPNs:
> >  > 
> >  >  9 Mar 08:08:58 ntpd[1510]: Listening on interface #6 wlan0, 192.168.75.58#123 Enabled
> >  >  9 Mar 08:09:00 ntpd[1510]: Listening on interface #7 tun0, 193.196.120.15#123 Enabled
> >  >  9 Mar 08:09:04 ntpd[1510]: Listening on interface #8 tun1, 141.3.162.67#123 Enabled
> >  > 
> >  > Over interface #8 some of the servers are actually available, but
> >  > ntpq -p still states:
> >  > No association ID's returned
> >  > 
> >  > Only when I restart ntpd, it operates as expected:
> >  >      remote           refid      st t when poll reach   delay   offset  jitter
> >  > ==============================================================================
> >  >  zit-net2.uni-pa .STEP.          16 u    -  512    0    0.000    0.000   0.000
> >  >  alpha.rueckgr.a .STEP.          16 u    -  512    0    0.000    0.000   0.000
> >  >  ntp.goneco.de   .STEP.          16 u    -  512    0    0.000    0.000   0.000
> >  > +proxy4.rz.uni-k 129.13.64.17     2 u   30  128  271    2.937    2.530   1.891
> >  > +proxy2.rz.uni-k 129.13.64.17     2 u   58  128  375    3.593   -8.981   1.837
> >  > *proxy1.rz.uni-k 129.13.64.17     2 u   15  128  271    3.297    8.244   1.487
> > 
> > I've always had to restart named after losing / regaining an interface, 
> > most noticeably after a suspend/resume (eg a low battery suspend), so I 
> > run /etc/rc.d/named restart from rc.resume.  This looks like a similar 
> > issue perhaps, though I don't see why restarting only ntpd would fix it.
> 
> As I said, named doesn't run at all. When the notebook gets an
> internet connection, ntpd recognizes this. It somehow doesn't
> occur to it, though, that it might be able to resolve the
> servers, now.

I believe this is the problem.  Note that you'll need to add an SSL
cert. exception for this site due to them using self-signed certs.

https://support.ntp.org/bugs/show_bug.cgi?id=987

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |