cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
2883
Views
0
Helpful
5
Replies

NTP-5-PEERSYNC: NTP synced logging ?

kthned
Level 3
Level 3

Hi Networkers,

I would like your help on diagonosis the NTP problem on a 6500 switch.

I have configured a single NTP public server and three peers on Switch 'A' and two server and two peer on the 6500 switches with the following straight forward commands. The "sh ntp association" shows the switches are sync with NTP server xx.xx.xx.xx.

ntp logging

ntp clock-period xxx

ntp source Loopback0

ntp access-group peer x

ntp access-group serve-only x

ntp update-calendar

ntp server xx.xx.xx.xx

ntp peer x.x.x.x

ntp peer y.y.y.y

ntp peer z.z.z.z

On switch 'A', I see following NTP logging 7-8 times a day "NTP synced to peer" but on the second switch, it is quite stable, I dont see such messages on switch A. both switch A (12.2(50r)SYS2) & B (12.2(17r)SX3) uses different IoS.

Oct 15 08:36:41.324: %NTP-5-PEERSYNC: NTP synced to peer xx.xx.xx.xx

Please help me why I see different behaviour provided the same ntp server is configured on both switch ?

Regards,

Umair

Message was edited by: Syed Umair Ali  

5 Replies 5

ciscoamit_497
Level 1
Level 1

DId u check the link that is being used by NTP server to access server time..??

If there is no issue with that then it could be issue with the IOS on switch A.

Can you post show ntp assosciation of both the switches..

Regards,

Amit

********Keep rated helpful posts*******

Hi

here is the output of sh ntp associations. I dont understand why switch keep on coming with "peersync" when there is no reachability issues. What could be the reason of "peersync" log messags ?

switch A#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp

*~xx.xx.xx.xx      .GPS.             1   743  1024  357    32.0   -5.77    16.4

+~192.x.x.xx    x.x.x.x      2   987  1024  376    17.2    6.05    24.3

+~192.xx.x.xx     x.x.x.x     2   532  1024  377     0.8   -2.27    16.1

+~192.xx.xx.xx     x.x.x.x      2   448  1024  332     0.2   -0.62     6.7

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

swictB #sh ntp associations

  address         ref clock       st   when   poll reach  delay  offset   disp

*~x.x.x.x.     .GPS.            1    502    512   377 29.642  -1.229 11.017

-~x.x.x.x. x.x.x.x.     2    441    512   377  0.725   0.926 12.927

-~x.x.x.x    x.x.x.x    2    463    512   377  0.900   0.039 11.034

+~y.y.y.y    .GPS.            1      3    256   377 21.414  -0.518  9.115

* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

One thing to add here is the switch B is having 2 server & 2 peer while switch A has one server and two peer.

Message was edited by: Syed Umair Ali

Dear Syed,

You can

TRY THIS:

1. Make sure that above mentioned NTP server(s) is reachable by pinging the server

   IP address(es).

2. Issue the command

show ntp status

on the server(s) to make sure that NTP server

   has synched itself. If it is not synched, verify the server NTP configuration.

   The

show ntp status

of the server should display a status of 'sync' before

   clients can sync their clock with the server. If the NTP server is not synchronized

   itself try to disable and re-enable the NTP configuration on the server.

3. Verify that the 'stratum' value configured on the server is valid for your setup.

   Configure a high stratum number to ensure that this router does not override

   the clock on another system with a lower stratum number. The lower stratum number

   indicates a more reliable clock.

4. If authentication is configured between the server and the client, make sure

   that authentication-key

number

and md5

key

value matches. Also, verify that

   the command

ntp server {server_address} key {key}

is included in the client

   configuration.

5. Make sure that NTP packets are not blocked by the access-list statement

switch A#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp

*~xx.xx.xx.xx      .GPS.             1   743  1024  357    32.0   -5.77    16.4

+~192.x.x.xx    x.x.x.x      2   987  1024  376    17.2    6.05    24.3

+~192.xx.x.xx     x.x.x.x     2   532  1024  377     0.8   -2.27    16.1

+~192.xx.xx.xx     x.x.x.x      2   448  1024  332     0.2   -0.62     6.7

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

swictB #sh ntp associations

  address         ref clock       st   when   poll reach  delay  offset   disp

*~x.x.x.x.     .GPS.            1    502    512   377 29.642  -1.229 11.017

-~x.x.x.x. x.x.x.x.     2    441    512   377  0.725   0.926 12.927

-~x.x.x.x    x.x.x.x    2    463    512   377  0.900   0.039 11.034

+~y.y.y.y    .GPS.            1      3    256   377 21.414  -0.518  9.115

* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

TRY THIS:
1. Make sure that above mentioned NTP server(s) is reachable by pinging the server
   IP address(es).
2. Issue the command show ntp status on the server(s) to make sure that NTP server
   has synched itself. If it is not synched, verify the server NTP configuration.
   The show ntp status of the server should display a status of 'sync' before
   clients can sync their clock with the server. If the NTP server is not synchronized
   itself try to disable and re-enable the NTP configuration on the server.
3. Verify that the 'stratum' value configured on the server is valid for your setup.
   Configure a high stratum number to ensure that this router does not override
   the clock on another system with a lower stratum number. The lower stratum number
   indicates a more reliable clock.
4. If authentication is configured between the server and the client, make sure
   that authentication-key number and md5 key value matches. Also, verify that
   the command ntp server {server_address} key {key} is included in the client
   configuration.
5. Make sure that NTP packets are not blocked by the access-list statement

If all these statement is not helpful then do a ping long reply ping test to check the stability of the network...

Hope this would be helpful to you...

And aaccording to the output--

switch A#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp

*~xx.xx.xx.xx      .GPS.             1   743  1024  357    32.0   -5.77    16.4    

+~192.x.x.xx    x.x.x.x      2   987  1024  376    17.2    6.05    24.3

+~192.xx.x.xx     x.x.x.x     2   532  1024  377     0.8   -2.27    16.1

+~192.xx.xx.xx     x.x.x.x      2   448  1024  332     0.2   -0.62     6.7

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

swictB #sh ntp associations

  address         ref clock       st   when   poll reach  delay  offset   disp

*~x.x.x.x.     .GPS.            1    502    512   377 29.642  -1.229 11.017     <<<<<

-~x.x.x.x. x.x.x.x.     2    441    512   377  0.725   0.926 12.927

-~x.x.x.x    x.x.x.x    2    463    512   377  0.900   0.039 11.034

+~y.y.y.y    .GPS.            1      3    256   377 21.414  -0.518  9.115

* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

You can refer below diagnostics link that may help you---

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080a23d02.shtml

https://supportforums.cisco.com/docs/DOC-1263

Hope all will be helpful to u...

Please keep us updated about ur issue and if solved then pls inform...and rate the helpful post...

Amit

Hi Amit

you deadly pointed the cause and I can see the peer-sync logs on switch A. but the question is why switch A has synching problem while Switch B doesnot ? 

Regards,

Umair

Umair,

I have seen ur show ntp associations command on primary switch and found the port number is not right as it should 377.

Please use debug commands mentioned in the second link...it will definitely help you to indentify the issue...

Let me know ur further steps..

Amit

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Innovations in Cisco Full Stack Observability - A new webinar from Cisco