NTP synchronization issue

[randms2610]

Hi, i'm having a problem with my NTP configuration

this is the topology

|win ntp server (newly added)| ----- |cat4500 core switch| ------ |other network device|

the original config from my predecessor is making the cat4500 as the NTP source for all device, but this was before we add a new win NTP server.

after we add a new win NTP server, we changed the cat4500 config so it will not act as the ntp source anymore and sync to the new NTP server instead.

everything is ok on the cat4500 and it can sync successfully with the new win NTP server.

meanwhile, all other network device is still pointing to cat4500 for syncing. 

the problem is inconsistency. on some device, it says that the clock is synced successfully but it showing wrong time.. while on some other device, it shows the right time but saying that it is not successfully synced.

is there any other solution without having to manually change the ntp server IP on other device one by one?

thanks

[Leo Laohoo]

the original config from my predecessor is making the cat4500 as the NTP source for all device, but this was before we add a new win NTP server.

after we add a new win NTP server, we changed the cat4500 config so it will not act as the ntp source anymore and sync to the new NTP server instead.

This is one case where I will say "if it ain't broke, don't fix it".  

Microsoft DO NOT adhere to NTP/SNTP standard.  This is why when the role was switched the 4500 won't synch to the Windows NTP "server".  

[kevin.szatkowski]

randms2610, 

     Can you describe what the other networking devices are?  Are they routers and switches, client systems, servers, etc...

[randms2610]

hello, by the "other" networking device i mean other cisco device, like cat3560 and cat2960s, they act as my distribution and access switches.... and they got "ntp server x.x.x.x" configured where x.x.x.x is the cat4500 IP. 

all other appliances like my firewall, proxy, etc, are syncing directly to the new NTP server and no problem. I just try to find a way so that I dont have to change NTP server configuration on my other 96 switches :)

what i want is something like this:

- cat4500 get time from new NTP server

- other switches get time from cat4500

is it possible to have this without any issue?

[kevin.szatkowski · Accepted solution]

What ios is the cat4500 running?  Just off the top of my head you can keep the client on the cat4500 and it's either turn on NTP broadcast on each LAN interface which you wish to broadcast NTP or possibly the ntp master command.  How is the other 96 switches connected? Layer 2/3.

Or you can just point the 96 switches to NTP, look into putty commander or other versions that allow you to replicate commands across multiple devices.  Another options is to look into automation with a tool like ansible.

Looking forward to your reply.  Kevin

[randms2610]

Hi, sorry for the late reply.. thanks for the suggestion

I finally took the simple way of changing NTP configuration on all switches, using 3rd party automation software. Maybe sometimes you can't solve it for free :)

[randms2610]

thanks for the reply, i agree with you "if it aint broke, dont fix it" , totally agree

however, it was done to comply with the company IT standard :)

and there is no issue on the cat4500 syncing with the windows NTP server... the issue is for the other device "behind" that cat4500