[ntp:questions] ntpd not talking to servers? (was Re: SIGINFO for Portable OpenNTP on Linux)

RedGrittyBrick RedGrittyBrick at spamweary.invalid
Fri Sep 4 16:11:43 UTC 2009


Ronan Flood wrote:
> RedGrittyBrick <RedGrittyBrick at spamweary.invalid> wrote:
> 
>> So, no contact with NTP servers after 40 mins of running, even though 
>> ntpdate can query those same servers quite happily.
> 
> "ntpdate -q" uses a high local port, ntpd uses local port 123.

Oh, OK.

> If you stop ntpd, does "ntpdate", without -q or -u or -d, work?


# ntpdate
  4 Sep 16:35:22 ntpdate[3523]: no servers can be used, exiting

# /etc/init.d/ntpd stop
Shutting down ntpd:                                        [  OK  ]

# /etc/init.d/ntpd status
ntpd is stopped

# ntpdate
  4 Sep 16:35:49 ntpdate[3543]: no servers can be used, exiting

> If not, perhaps a firewall issue.

The openntpd daemon seemed to be able to talk to servers, here's some 
syslog records from it:

Sep  4 09:47:27 amber ntpd[1261]: ntp engine ready
Sep  4 09:47:44 amber ntpd[1261]: peer 212.13.195.3 now valid
Sep  4 09:47:45 amber ntpd[1261]: peer 93.89.85.202 now valid
Sep  4 09:47:49 amber ntpd[1261]: peer 194.238.48.3 now valid
Sep  4 09:47:50 amber ntpd[1261]: peer 91.213.50.15 now valid
Sep  4 09:47:51 amber ntpd[1261]: peer 82.219.4.30 now valid
Sep  4 10:03:52 amber ntpd[1261]: clock is now synced
Sep  4 10:16:51 amber ntpd[1261]: peer 93.89.85.202 now invalid
Sep  4 10:28:20 amber ntpd[1261]: peer 93.89.85.202 now valid
Sep  4 10:31:24 amber ntpd[1261]: clock is now unsynced
Sep  4 10:50:52 amber ntpd[1261]: clock is now synced
Sep  4 11:08:28 amber ntpd[1260]: adjusting local clock by -0.135589s
Sep  4 11:32:22 amber ntpd[1261]: clock is now unsynced
Sep  4 11:40:02 amber ntpd[1261]: peer 194.238.48.3 now invalid
Sep  4 11:40:57 amber ntpd[1261]: peer 93.89.85.202 now invalid
Sep  4 11:42:30 amber ntpd[1261]: clock is now synced
Sep  4 11:53:33 amber ntpd[1261]: peer 194.238.48.3 now valid
Sep  4 11:53:53 amber ntpd[1261]: peer 93.89.85.202 now valid
Sep  4 12:28:08 amber ntpd[1260]: adjusting local clock by -0.191927s
Sep  4 12:37:32 amber ntpd[1261]: clock is now unsynced
Sep  4 12:57:26 amber ntpd[1261]: clock is now synced
Sep  4 13:37:16 amber ntpd[1260]: adjusting local clock by -0.190155s
Sep  4 13:37:16 amber ntpd[1261]: clock is now unsynced
Sep  4 13:44:14 amber ntpd[1261]: clock is now synced
Sep  4 13:47:21 amber ntpd[1261]: peer 194.238.48.3 now invalid
Sep  4 13:58:46 amber ntpd[1261]: peer 194.238.48.3 now valid
Sep  4 14:05:51 amber ntpd[1261]: peer 212.13.195.3 now invalid
Sep  4 14:19:06 amber ntpd[1261]: peer 212.13.195.3 now valid
Sep  4 14:31:32 amber ntpd[1260]: adjusting local clock by -0.137812s
Sep  4 14:31:32 amber ntpd[1261]: clock is now unsynced
Sep  4 14:44:28 amber ntpd[1260]: adjusting local clock by -0.154506s
Sep  4 14:44:28 amber ntpd[1261]: clock is now synced
Sep  4 14:53:47 amber ntpd[1260]: adjusting local clock by -0.170122s
Sep  4 14:58:06 amber ntpd[1261]: clock is now unsynced
Sep  4 15:00:12 amber ntpd[1261]: ntp engine exiting
Sep  4 15:00:12 amber ntpd[1260]: Terminating

I can't say I follow what it is doing, but I do get the impression it is 
able to talk to NTP servers.

A non-Linux server on the same LAN can use ntpd OK.

A Windows XP client can get time from 0.uk.pool.ntp.org using UDP on 
port 123. A sniffer (Wireshark) shows NTP version 3 packets.

Here's what tcpdump has to say on the non-working box when I start ntpd

# tcpdump -s0 port 123
tcpdump: listening on eth0
17:03:10.167926 amber.my.domain.ntp > razor.peloris.co.uk.ntp:  v4 
client strat 0 poll 6 prec -17 (DF) [tos 0x10]
17:03:10.231563 razor.peloris.co.uk.ntp > amber.my.domain.ntp:  v4 
server strat 2 poll 6 prec -20 (DF)
17:03:19.167366 amber.my.domain.ntp > ntp0.lon.bitfolk.com.ntp:  v4 
client strat 0 poll 6 prec -17 (DF) [tos 0x10]
17:03:19.223485 ntp0.lon.bitfolk.com.ntp > amber.my.domain.ntp:  v4 
server strat 3 poll 6 prec -20 (DF)
17:03:20.167292 amber.my.domain.ntp > ntp1.arse.org.ntp:  v4 client 
strat 0 poll 6 prec -17 (DF) [tos 0x10]
17:03:23.167106 amber.my.domain.ntp > ntp1.exa.net.uk.ntp:  v4 client 
strat 0 poll 6 prec -17 (DF) [tos 0x10]
17:03:23.215801 ntp1.exa.net.uk.ntp > amber.my.domain.ntp:  v4 server 
strat 2 poll 6 prec -20 (DF)

# ntpq -p
      remote           refid      st t when poll reach   delay   offset 
  jitter
==============================================================================
  ntp1.arse.org   0.0.0.0         16 u    -   64    0    0.000    0.000 
4000.00
  ntp0.lon.bitfol 0.0.0.0         16 u    -   64    0    0.000    0.000 
4000.00
  ntp1.exa.net.uk 0.0.0.0         16 u    -   64    0    0.000    0.000 
4000.00
  razor.peloris.c 0.0.0.0         16 u    -   64    0    0.000    0.000 
4000.00


Odd eh? There's network traffic. Why doesn't it show up in `ntpq -p`?

-- 
RGB




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