Cisco 3750 is not getting sync with NTP server located in our HO

[mainodin87]

Hey Guys,

Need solution on suggestions please,

I have Cisco 3750 here in branch office and NTP server is configured and located in our HO, the problem is i have entered all required commands to sync my 3750 with our NTP but still its showing,

"Clock is unsynchronized, stratum 16, no reference clock"

Please get me out from this !

Thank you

[Dan Lukes]

Wrong community for your question. Please use blue [ EDIT ] button to move it to Other Network Infrastructure Subjects if you wish for reply.

[LJ Gabrillo]

That's not a configuration issue, that is most likely an NTP server issue?

What NTP server is that?

In my experience, i've used Windows native time (w32tm)
Enabling NTP feature on the server requires additional tweaking on the registry

[mainodin87]

Hi Gabrillo,

we have same like you have used but it's located in HO, for which i dont have access, if you can suggest me what feature needs to be enabled/checked on NTP  then i can mail it to concern team for same.

Thank you,

[LJ Gabrillo]

Note that you will need to change the registry of the server. It would be best to deploy a dedicated Windows Server for NTP

Just do the ff. on the registry:

    AT: HKEY_LOCAL_MACHINE->SYSTEM->CurrentControlSet->services->W32Time
   CHANGE:
   Config:     "LocalClockDispersion"="0"   -DWORD  ->>IMPT!!

   Parameters: "Type"="NTP"                 -STRING
               "NtpServer"="127.1.1.1,0x8"  -STRING
               "ReliableTimeSource"="1"     -DWORD

   TimeProviders->NtpServer: "Enabled"="1"  -DWORD  ->>IMPT!!
 

Note if the registry entry does not exist, create one for it

[mainodin87]

Hey Gabrillo,

Thanks for the suggestion will mail the same to concern team, lets wait for their revert will get back to you soon.

Regards,

Mainodin

[LJ Gabrillo]

NP, I have already tried multiple times setting up windows Server for NTP for Cisco, just make sure the registry values exist and it should work

PS: Make sure Port 123/UDP is open on the server. this is the NTP port

[rosaho]

This discussion has been reposted from Network Management to the Other Network Infrastructure Subjects community.

[mainodin87]

Hey Gabrillo,

Thanks for your suggestion, now the issue is resolved.

The problem was with the firewall, security team replied stating "there was wrong URL mentioned in policy for NTP server".

Don't know in detail about that but now its getting synchronized with NTP.

Regards,

Mainodin

[LJ Gabrillo]

Nice to know you found the issue.
Most likely they might have configured the wrong firewall policy

Glad to know it's working


Cheers,

[LJ Gabrillo]

Don't forget to rate our suggestions so everyone can see 
​additionally, this will mark this section answered/closed :D

[mainodin87]

Hey Gabrillo,

Backend team is still working on it, i have provided your suggestion to them, once the issue is resolved will surely post it here with exact root cause.

Regards,

Mainodin

[LJ Gabrillo]

Just update us here Mainodin,

Oh yeah, just a heads up, I have deployed quite a few of Windows Servers as NTP, so all those settings should work


For verification sake, on your server you can execute the ff. commands:
>net time  


I almost forgot, you need to do the ff. steps below:
1. Make sure/Verify w32time feature is running/enabled
    -At windows services, kindly check if: "Windows Time" service is running, if not, enable it and set it to automatic(in case of server reboot it will auto start)

2. Execute CMD command
>w32tm /config /reliable:yes /update

>net time         -Verify