NTP server

Answered Question
Oct 30th, 2008
User Badges:

we have a NTP server and a few switches, configuratio is:


ntp server 10.0.89.17

ntp update-calendar


we can get the time from NTP server as "show NTP asso detail":

but we noticed some switched time quite different:

___________________________________________

switch1#sh clock

*21:22:57.972 SGT Thu Oct 30 2008

____________________________________________

switch1#sh ntp a de

10.0.89.17 configured, insane, invalid, stratum 1

ref ID .LOCL., time CCB3D970.A15A6754 (14:57:52.630 SGT Thu Oct 30 2008)

our mode client, peer mode server, our poll intvl 1024, peer poll intvl 1024

root delay 0.00 msec, root disp 10278.05, reach 377, sync dist 10284.561

delay 1.57 msec, offset -235174.3695 msec, dispersion 5.74

precision 2**6, version 3

org time CCB43204.03E9C37D (21:15:48.015 SGT Thu Oct 30 2008)

rcv time CCB432EF.30C0E6B1 (21:19:43.190 SGT Thu Oct 30 2008)

xmt time CCB432EF.30599444 (21:19:43.188 SGT Thu Oct 30 2008)

filtdelay = 1.57 1.51 1.57 1.59 1.42 1.60 1.62 1.56

filtoffset = -235174 -235169 -235167 -235166 -235173 -235167 -235158 -235166

filterror = 0.02 7.83 11.73 13.69 14.66 15.32 16.30 17.27

____________________________________

switch2#sh clock

.21:16:00.383 SGT Thu Oct 30 2008

____________________________________

switch2#sh ntp a d

10.0.89.17 configured, insane, invalid, stratum 1

ref ID .LOCL., time CCB3D970.A151F81A (14:57:52.630 SGT Thu Oct 30 2008)

our mode client, peer mode server, our poll intvl 512, peer poll intvl 256

root delay 0.00 msec, root disp 10279.97, reach 377, sync dist 10285.385

delay 1.24 msec, offset 208528.7231 msec, dispersion 4.81

precision 2**6, version 3

org time CCB432AB.239FCB0C (21:18:35.139 SGT Thu Oct 30 2008)

rcv time CCB431DA.9C6E2924 (21:15:06.611 SGT Thu Oct 30 2008)

xmt time CCB431DA.9C1CA251 (21:15:06.609 SGT Thu Oct 30 2008)

filtdelay = 1.24 1.02 1.30 1.27 1.28 1.24 1.24 1.36

filtoffset = 208528. 208523. 208525. 208533. 208524. 208533. 208543. 208534.

filterror = 0.02 0.99 1.91 2.88 3.86 4.84 5.81 6.79

can someone tell us where is the problem?

thanks

Correct Answer by Richard Burts about 8 years 7 months ago

bindong


Since I do not know how your Windows server is configured and what, if any, supplemental services it might be running, I can not confirm that it is the cause of the insane, invalid. But this link does confirm that the normal Windows Time Service is an implementation of SNTP:

http://support.microsoft.com/kb/224799

and here is a quote from that article:

The Windows Time Synchronization service (W32Time) is a fully compliant implementation of the Simple Network Time Protocol (SNTP) as detailed in IETF RFC 1769.


And I can confirm that an NTP client will not learn time from a SNTP server. So it is a logical conclusion that the server running SNTP is the cause of the insane, invalid.


HTH


Rick

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (2 ratings)
Loading.
Richard Burts Thu, 10/30/2008 - 07:00
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

bindong


I do not believe that we have enough information available to fully solve your issue. But one thing is clear from what you poasted: neither switch is learning its time from the configured server. Both switches have this in their output:

switch2#sh ntp a d

10.0.89.17 configured, insane, invalid, stratum 1

This indicates that the server that is configured is invalid and the switch is not learning time from it.


What can you tell us about the configured ntp server? What kind of device is it? Where is it learning its time?


HTH


Rick

shibindong Thu, 10/30/2008 - 07:04
User Badges:

thanks for your reply!


our NTP server is windows server. I just realized "insane, invalid" in the output means sync fail. is it becasue of Windows running SNTP instead of NTP?

Richard Burts Thu, 10/30/2008 - 07:07
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

bindong


I suspect that the insane, invalid is because the Windows server is running SNTP rather than NTP.


HTH


Rick

shibindong Thu, 10/30/2008 - 07:09
User Badges:

is there any document can help us to verify that?

because you just "suspect", can you comfirm?

Correct Answer
Richard Burts Thu, 10/30/2008 - 07:19
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

bindong


Since I do not know how your Windows server is configured and what, if any, supplemental services it might be running, I can not confirm that it is the cause of the insane, invalid. But this link does confirm that the normal Windows Time Service is an implementation of SNTP:

http://support.microsoft.com/kb/224799

and here is a quote from that article:

The Windows Time Synchronization service (W32Time) is a fully compliant implementation of the Simple Network Time Protocol (SNTP) as detailed in IETF RFC 1769.


And I can confirm that an NTP client will not learn time from a SNTP server. So it is a logical conclusion that the server running SNTP is the cause of the insane, invalid.


HTH


Rick

Actions

This Discussion