topic NTP Server and Clients - LAN in Network Security

NTP Server and Clients - LAN

inshu.inshu — Fri, 21 Feb 2020 12:00:34 GMT

Hi,

I need to create NTP server and clients on my network.I have a core 4507 and access 2960 series switches.

Would like to know if there is a hardware clock built in for the cisco 4500 series switches, if yes I am planning to make it as my NTP server.

Kindly let me know the procedure to make 4500 as my NTP server and all other 2960 switches as clients.

Thanks & Regards,

Re: NTP Server and Clients - LAN

Ganesh Hariharan — Thu, 01 Jul 2010 08:14:24 GMT

Hi,
I need to create NTP server and clients on my network.I have a core 4507 and access 2960 series switches.
Would
like to know if there is a hardware clock built in for the cisco 4500
series switches, if yes I am planning to make it as my NTP server.
Kindly let me know the procedure to make 4500 as my NTP server and all other 2960 switches as clients.
Thanks & Regards,
MI

Hi MI,

Check out the below link for ntp configuration on 4500 series switches

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/31sga/configuration/guide/swadmin.html#wp1245641

Hope to Help !!

Ganesh.H

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Re: NTP Server and Clients - LAN

inshu.inshu — Thu, 01 Jul 2010 09:04:18 GMT

Hi Ganesh,

Thanks for your concern and reply.

You know what I have this PDF with me which came along with the switch.

I am looking for someone who can guide on how to do this, I did try the one in the link which you provided.

Below are the outputs for the same.

Core(config)#ntp authenticate
Core(config)#ntp authentication-key 1 md5 aNiceKey
Core(config)#ntp trusted-key 1
Core(config)#end

Core(config)#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**18
reference time is 00000000.00000000 (00:00:00.000 SA Mon Jan 1 1900)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec
Core#sh ntp association

address ref clock st when poll reach delay offset disp
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

I did enter the core ip in one of the client and tried to synchronize its not happening.

Later when I enter ntp master in core, the clock got synchronized only in core.

It would be great if you know and if you did it right and then post replies.

Kindly just dont try to provide the cisco links which anybody can search and reach out.

Thanks again,

Re: NTP Server and Clients - LAN

Ganesh Hariharan — Thu, 01 Jul 2010 09:07:56 GMT

Hi Ganesh,

Thanks for your concern and reply.

You know what I have this PDF with me which came along with the switch.

I am looking for someone who can guide on how to do this, I did try the one in the link which you provided.

Below are the outputs for the same.

Core(config)#ntp authenticate
Core(config)#ntp authentication-key 1 md5 aNiceKey
Core(config)#ntp trusted-key 1
Core(config)#end

Core(config)#sh ntp status

address ref clock st when poll reach delay offset disp
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

I did enter the core ip in one of the client and tried to synchronize its not happening.

Later when I enter ntp master in core, the clock got synchronized only in core.

It would be great if you know and if you did it right and then post replies.

Kindly just dont try to provide the cisco links which anybody can search and reach out.

Thanks again,

Hi MI,

If you want your cisco 4500 to act as ntp server for your local lan

Then issue these commands ntp master 3 and in client switches just configure ntp 4500 switch ip address to sync with clock of 4500 switch.

Hope to help !!

Ganesh.H

Remember to rate the helpful post

Re: NTP Server and Clients - LAN

inshu.inshu — Thu, 01 Jul 2010 09:48:20 GMT

Hi Ganesh,

Thanks much for your earliest reply.

I did the same on the switches and WOW..it jus got worked.

I have enough client switches to be configured, I would come back to rate your post.

Let me ask you, wont I be able to see the associated devices from the core? I did see that one of my client is showing its associated to my core, my things are working good here, this is just to keep my knowledge updated.

Core#sh ntp status
Clock is synchronized, stratum 3, reference is 127.127.7.1
nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**18
reference time is CFD67BED.FBE99CB2 (02:29:01.984 SA Thu Jul 1 2010)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.02 msec, peer dispersion is 0.02 msec

Core#sh ntp association

address ref clock st when poll reach delay offset disp
*~127.127.7.1 127.127.7.1 2 48 64 377 0.0 0.00 0.0
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

####################################################################################

swB_M2_48#sh ntp status
Clock is synchronized, stratum 4, reference is 10.20.4.1
nominal freq is 119.2092 Hz, actual freq is 119.2092 Hz, precision is 2**18
reference time is CFD67C02.90A53A52 (02:29:22.565 UTC Thu Jul 1 2010)
clock offset is -0.6040 msec, root delay is 2.21 msec
root dispersion is 3875.96 msec, peer dispersion is 3875.32 msec
swB_M2_48#sh ntp association

address ref clock st when poll reach delay offset disp
*~10.20.4.1 127.127.7.1 3 0 64 377 1.7 -0.23 0.4
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
#####################################################

Thanks & Best Regards,

Re: NTP Server and Clients - LAN

Ganesh Hariharan — Thu, 01 Jul 2010 10:47:10 GMT

Hi Ganesh,

Thanks much for your earliest reply.

I did the same on the switches and WOW..it jus got worked.

I have enough client switches to be configured, I would come back to rate your post.

Core#sh ntp association

address ref clock st when poll reach delay offset disp
*~127.127.7.1 127.127.7.1 2 48 64 377 0.0 0.00 0.0
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

####################################################################################

Hi MI,

Check out the below link on the above query asked !!

http://www.cisco.com/en/US/products/sw/iosswrel/ps1818/products_tech_note09186a008015bb3a.shtml

Hope to Help !!

Ganesh.H

Remember to rate the helpful post