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NTP implementation

Hi all,

I am currently deploying NTP on a heterogenous network (~100 routers) and I have a lot of issues to synchronise all of them.

I use Server/client configuration because of WAN accesses with this configuration as example :


service timestamps debug datetime msec localtime

service timestamps log datetime msec localtime


clock timezone GMT 0


ntp source Loopback0

ntp server BCKUP_RT key 1

ntp server MASTER_RT key1 prefer

ntp authentication-key 1 md5 CiScO1

ntp authenticate

ntp trusted-key 1


Now, it's going to be a nightmare to understand why this is not working on one equipment and working on other...

After to check and compare all the differences on my matrix I had exactly the result see below (please consider that Models are exactly with the same hardware -memory-line cards-...):

Here is the matrix :

Name Models Version NTP Working

TOTO1 2500 11.2(16) YES

TOTO2 2500 11.2(16) NO

TOTO3 2500 11.2(16)P YES

TOTO4 2500 11.2(16)P NO

TOTO5 7200 11.2(16)P YES

TOTO6 2610XM 12.2(17) YES

TOTO7 2610XM 12.2(17) NO

TOTO8 2610XM 12.1(17) YES

TOTO9 2610XM 12.1(17) NO

It seems that NTP is not well supported or integrated on the Cisco's equipment ?

If someone can help me to solve this... I will be thanksfull ;o)

Thanks in advance


  • Other Network Infrastructure Subjects
VIP Purple

Re: NTP implementation

Hello Sébastien,

I assume you have verified that all routers can reach the ntp master. Can you post the output of:

debug ntp authentication

debug ntp events

debug ntp packets

and also the output of the

show ntp association detail

command executed on a router that does synchronize and a router that does not synchronize ?



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