NTP configuration on a 4507R

[Brent Rockburn]

Can someone point me to a good config doc for NTP on a 4500 switch. I can't seem to find anything decent.

Thanks in advance,

Brent

PS: I mean how to configure a 4500 switch to be the NTP master that all others come to for accurate time...

[Sebastian Helmer]

Hey,

I would say this should help you..

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/54sg/configuration/guide/swadmin.html#wp1245608

best,

Sebastian

[Leo Laohoo]

I wouldn't configure Cisco appliance as an authoritative NTP server (ntp master).

If you have Windows servers, you can configure them to be an authoritative NTP server.

How to configure an authoritative time server in Windows XP
http://support.microsoft.com/kb/314054

How to configure an authoritative time server in Windows Server
http://support.microsoft.com/kb/816042

How to configure an authoritative time server in Windows 2000
http://support.microsoft.com/kb/216734

Sure, all of your switches can get their time sync on your 4507R but you don't have to configure "ntp master" to it.  Just point your switches to it using the command "ntp server [prefer]".

The reason why I don't recommend a Cisco appliance as an authoritative NTP/SNTP server is because the clock chip is similar to a PC.  It doesn't have a dedicated method of verifying.  You can, however, let your 4507R synchronize it's own clock with something that is authoritative.  You can get a cheap NTP server that uses GPS (best method so far).  Another option is to open a port in the firewall to allow the  4507Rto talk to world-wide NTP pool.