[ntp:questions] Too high steps in time reset

massimo.musso at gmail.com massimo.musso at gmail.com
Tue Apr 22 06:55:01 UTC 2008


Hello everybody.

Since years, I've configured a ntp server to keep aligned thousand of
host in a private network where the time is vital.
But in the last month I experienced a problem because my ntp server
syncronize resets time with large steps (5-20 seconds) and this causes
problems in my network. I don't understand how can it happen.

My ntp server is a Linux RedHat 7.3 server and, shortly, /etc/ntp.conf
is configured in this way:
--------------------------------------------------------------------------------------------------------------
restrict default nomodify notrap noquery
restrict 127.0.0.1
driftfile /var/lib/ntp/drift
broadcastdelay  0.008
keys            /etc/ntp/keys
broadcastclient
server 172.31.1.90
server 193.204.114.232
server 127.127.1.0
fudge   127.127.1.0 stratum 10
restrict 172.31.1.90 mask 255.255.255.255 nomodify notrap noquery
--------------------------------------------------------------------------------------------------------------
the first server (172.31.1.90) is a dcf77 stratum 11 in my LAN,
syncronizing itself 2/3 times per day
the second server is an Internet ntp server stratum 1, IEN Galileo
Ferraris
both servers are ok and there is no difference in time (i.e.
milliseconds)

this is the today's log file:
--------------------------------------------------------------------------------------------------------------
Apr 22 00:15:09 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 00:32:16 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 00:49:16 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 01:06:23 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 01:23:29 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 01:57:36 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 02:14:46 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 02:48:51 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 03:40:07 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 03:57:19 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 04:14:17 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 04:31:24 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 05:22:36 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 05:39:47 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 05:56:46 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 06:13:49 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 06:48:03 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 07:22:16 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 07:22:26 gecssrv1 ntpd[20177]: time reset +9.470501 s
Apr 22 07:26:44 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
Apr 22 07:29:59 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 08:13:54 gecssrv1 ntpd[20177]: synchronized to LOCAL(0),
stratum 10
Apr 22 08:30:58 gecssrv1 ntpd[20177]: synchronized to 193.204.114.232,
stratum 1
--------------------------------------------------------------------------------------------------------------
You can see that at 7:22 I've got a time reset +9.4... that's HUGE. It
happens often.
The dcf77 sycronized at 5:40.
Does anyone can tell me how can it happen?

Thank you in advance.
Massimo




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