NTP problem

Unanswered Question
Dec 4th, 2007

Hello,

I want to configure routers to synchronise with a windows NTP server.

I have put the necessary commands

But it didn't work

**************************

ntp source Ethernet0/0

ntp server 172.17.4.70

*********************

********************************************************************

router#sh ntp associations

address ref clock st when poll reach delay offset disp

~172.17.4.70 0.0.0.0 16 45 64 0 0.0 0.00 16000.

* master (synced), # master (unsynced), + selected, - candidate, ~ configured

********************************************************************************

router#sh ntp associations detail

172.17.4.70 configured, insane, invalid, unsynced, stratum 16

ref ID 0.0.0.0, time 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)

our mode client, peer mode unspec, our poll intvl 64, peer poll intvl 64

root delay 0.00 msec, root disp 0.00, reach 0, sync dist 17.975

delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00

precision 2**5, version 3

org time CAFFAB77.CBC6A7EF (10:33:27.795 UTC Tue Dec 4 2007)

rcv time CAFF9D57.29DED560 (09:33:11.163 UTC Tue Dec 4 2007)

xmt time CAFF9D57.28FA6A59 (09:33:11.160 UTC Tue Dec 4 2007)

filtdelay = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

filtoffset = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

filterror = 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

*********************

debug

.Dec 4 11:47:31: NTP: xmit packet to 172.17.4.70:

.Dec 4 11:47:31: leap 3, mode 3, version 3, stratum 0, ppoll 64

.Dec 4 11:47:31: rtdel 0000 (0.000), rtdsp 0002 (0.031), refid 4C4F434C (76.79

.67.76)

.Dec 4 11:47:31: ref CAFFB529.0109F789 (11:14:49.004 UTC Tue Dec 4 2007)

.Dec 4 11:47:31: org CAFFBD77.D3F7CED8 (11:50:15.827 UTC Tue Dec 4 2007)

.Dec 4 11:47:31: rec CAFFBC93.03439624 (11:46:27.012 UTC Tue Dec 4 2007)

.Dec 4 11:47:31: xmt CAFFBCD3.0100F3B7 (11:47:31.003 UTC Tue Dec 4 2007)

.Dec 4 11:47:31: NTP: rcv packet from 172.17.4.70 to 172.17.4.1 on Ethernet0/0:

.Dec 4 11:47:31: leap 0, mode 4, version 3, stratum 2, ppoll 64

******************************************

What can be the probem

Thanks

I have this problem too.
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Kevin Dorrell Tue, 12/04/2007 - 05:51

It's a pity your debug doesn't include the detail of the packet received from the NTP server. However, I do notice that on your associations detail your receive time is an hour behind your transmit time, and in any case, they both think they are in UTC. So, I will take a guess that you are in CET timezone and you have not set up your router accordingly.

Please make sure your timezones are set up correctly. Foe continental Europe, this means:

clock timezone CET 1

clock summer-time CEST recurring last Sun Mar 2:00 last Sun Oct 3:00

Then have a look at your clock on the router and you will find that it looks 1 hour ahead. Now you can set the clock right - don't take the timezone out again.. set the clock so it is correct in your timezone.

THen leave it a couple of minutes and see if they synchonise a bit better. If not, then post again and I'll see if I can sort it out.

Kevin Dorrell

Luxembourg

fati20012 Tue, 12/04/2007 - 06:49

I put the two commands but still the same problem,

*************************************

router#debug ntp pac

.Dec 4 13:42:23: NTP: xmit packet to 172.17.4.70:

.Dec 4 13:42:23: leap 3, mode 3, version 3, stratum 0, ppoll 64

.Dec 4 13:42:23: rtdel 0000 (0.000), rtdsp 0002 (0.031), refid 4C4F434C (76.79

.67.76)

.Dec 4 13:42:23: ref CAFFB529.0109F789 (12:14:49.004 CET Tue Dec 4 2007)

.Dec 4 13:42:23: org CAFFE6A2.E3D70A3D (15:45:54.889 CET Tue Dec 4 2007)

.Dec 4 13:42:23: rec CAFFD77F.68C9490E (14:41:19.409 CET Tue Dec 4 2007)

.Dec 4 13:42:23: xmt CAFFD7BF.677218DB (14:42:23.404 CET Tue Dec 4 2007)

.Dec 4 13:42:23: NTP: rcv packet from 172.17.4.70 to 172.17.4.1 on Ethernet0/0:

.Dec 4 13:42:23: leap 0, mode 4, version 3, stratum 2, ppoll 64

.Dec 4 13:42:23: rtdel 0000 (0.000), rtdsp 0002 (0.031), refid 00000000 (0.0.0

.0)

.Dec 4 13:42:23: ref 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)

.Dec 4 13:42:23: org CAFFD7BF.677218DB (14:42:23.404 CET Tue Dec 4 2007)

.Dec 4 13:42:23: rec CAFFE6E2.E7EF9DB1 (15:46:58.905 CET Tue Dec 4 2007)

.Dec 4 13:42:23: xmt CAFFE6E2.E7EF9DB1 (15:46:58.905 CET Tue Dec 4 2007)

.Dec 4 13:42:23: inp CAFFD7BF.6920A04D (14:42:23.410 CET Tue Dec 4 2007)

Kevin Dorrell Tue, 12/04/2007 - 06:57

Your clock is (and always was) a hour out, which may be a bit far for it to capture. Leave the timezone at CET, and now correct your clock manually so it is a biit closer to the correct time.

(I presume you are actually in the CET zone. Where are you exactly? )

Also, I assume the time and time zone are correctly set up in your NTP server. Where does it take its reference from?

Please also post the associations now.

Kevin Dorrell

Luxembourg

fati20012 Tue, 12/04/2007 - 07:17

I'm in morocco, the server take its reference from its internal clock,

**************

Router#sh ntp status

Clock is unsynchronized, stratum 16, no reference clock

nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**24

reference time is CAFFB529.0109F789 (12:14:49.004 CET Tue Dec 4 2007)

clock offset is 0.0000 msec, root delay is 0.00 msec

root dispersion is 0.02 msec, peer dispersion is 0.02 msec

.Dec 4 15:13:40: NTP: xmit packet to 172.17.4.70:

.Dec 4 15:13:40: leap 3, mode 3, version 3, stratum 0, ppoll 64

.Dec 4 15:13:40: rtdel 0000 (0.000), rtdsp 0002 (0.031), refid 4C4F434C (76.79

.67.76)

.Dec 4 15:13:40: ref CAFFB529.0109F789 (12:14:49.004 CET Tue Dec 4 2007)

.Dec 4 15:13:40: org CAFFED22.E7EF9DB1 (16:13:38.905 CET Tue Dec 4 2007)

.Dec 4 15:13:40: rec CAFFECE4.6BBDB0E8 (16:12:36.420 CET Tue Dec 4 2007)

.Dec 4 15:13:40: xmt CAFFED24.6B624FCC (16:13:40.419 CET Tue Dec 4 2007)

.Dec 4 15:13:40: NTP: rcv packet from 172.17.4.70 to 172.17.4.1 on Ethernet0/0:

.Dec 4 15:13:40: leap 0, mode 4, version 3, stratum 2, ppoll 64

************************************

Router#sh ntp associations

.Dec 4 15:13:40: rtdel 0000 (0.000), rtdsp 0002 (0.031), refid 00000000 (0.0.0

.0)

.Dec 4 15:13:40: ref 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)

.Dec 4 15:13:40: org CAFFED24.6B624FCC (16:13:40.419 CET Tue Dec 4 2007)

.Dec 4 15:13:40: rec CAFFED62.EBC6A7EF (16:14:42.920 CET Tue Dec 4 2007)

.Dec 4 15:13:40: xmt CAFFED62.EBC6A7EF (16:14:42.920 CET Tue Dec 4 2007)

.Dec 4 15:13:40: inp CAFFED24.6DF77F71 (16:13:40.429 CET Tue Dec 4 2007)

**************************************

Router#sh ntp associations

address ref clock st when poll reach delay offset disp

~172.17.4.70 0.0.0.0 16 1 64 0 0.0 0.00 16000.

* master (synced), # master (unsynced), + selected, - candidate, ~ configured

*************************************

Router#sh ntp associations detail

172.17.4.70 configured, insane, invalid, unsynced, stratum 16

ref ID 0.0.0.0, time 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)

our mode client, peer mode unspec, our poll intvl 64, peer poll intvl 64

root delay 0.00 msec, root disp 0.00, reach 0, sync dist 160.706

delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00

precision 2**5, version 3

org time CAFFED62.EBC6A7EF (16:14:42.920 CET Tue Dec 4 2007)

rcv time CAFFED24.6DF77F71 (16:13:40.429 CET Tue Dec 4 2007)

xmt time CAFFED24.6B624FCC (16:13:40.419 CET Tue Dec 4 2007)

filtdelay = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

filtoffset = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

filterror = 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

Richard Burts Tue, 12/04/2007 - 07:19

Fatima

Perhaps we should find out a bit more about your environment and about your server to be able to give the best answer. Is the server really running NTP? Most Windows servers run the Windows Time Service which is based on SNTP not NTP itself. SNTP is a simplified protocol which requires fewer resources (and does not produce quite the level of accuracy - milliseconds - which NTP does).

HTH

Rick

fati20012 Wed, 12/05/2007 - 02:44

Hello,

you'are right, the server use the SNTp , i test with some routers that use sntp and it's ok.

Now what can i do for routers that use NTP to synchronise with this server.

Thanks a lot.

fati20012 Wed, 12/05/2007 - 04:42

Hello,

you'are right, the server use the SNTp , i test with some routers that use sntp and it's ok.

Now what can i do for routers that use NTP to synchronise with this server.

Thanks a lot.

Richard Burts Wed, 12/05/2007 - 08:49

Fatima

To give really good answers it would help if we understood more about your environment and about your real requirements.

But based on what we know so far, I will make a few suggestions. If it is important that the routers sync with the server, then perhaps you can run some application on the server that will learn time and will run NTP within the application. If the application is running NTP and has learned time, then the routers should be able to sync with the server. My personal opinion is that this is much more complicated than it is worth. But if it is really important that the routers sync with this server then this could be your solution.

Perhaps it will be just as good if the server and the routers sync with a common source. Perhaps the Domain Controller is doing a sync with some time server and then the routers might be able to sync with that time source also.

Perhaps your routers could use SNTP instead of NTP. I have not tested it but I assume that if the routers configured the server as sntp server rather than as ntp server I would assume that the routers would sync with the server ok. NTP is more accurate than SNTP, but for what most routers do with time I believe that SNTP is accurate enough.

HTH

Rick

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