Strange clock set

[rezaalikhani]

Yesterday, I set my switch 3550 clock by using the "clock set" command, but when I came back today to my switch, all may time settings had changed. why?

P.S. I do this procedure for using "time ACLs".

Thanx

Reza & Masoud

[peterledwidge]

Perhaps your switch reloaded and the configuration changes hadn't been saved to NVRAM.

check show version to see up time.

HTH

[farkascsgy]

Hi,

In your case I suggest to use NTP time server. You can synchronize all your network equipment to one central time server.

And don't forget save your config....

Bye

FCS

Please rate me if I helped.

[rezaalikhani]

Yes, I did save the configuration.

can I set the mentioned switch as a NTP server by specifying its IP address?

[Richard Burts]

Reza

Saving the configuration or not saving the configuration will not make any difference about the time being saved over a reload of the switch. Some Cisco devices have a calendar chip that will maintain time over a reload. Other Cisco devices do not have this chip and they will lose their time when they reload and it has nothing to do with saving the config. The suggestion about checking show version to verify whether the switch had reloaded or not is probably a good suggestion if you want to be sure of why the time changed.

As far as NTP is concerned you can make a Cisco device act as an NTP server by using the config command ntp master. I would suggest that you do this only on a device that has the calendar chip and will maintain time over a reload. Even better is to configure your Cisco routers and switches to learn time from some external NTP server.

HTH

Rick

[farkascsgy]

Answer:

The switch does not have a hardware-supported clock and cannot function as an NTP master clock to which peers synchronize themselves when an external NTP source is not available.

http://www.cisco.com/en/US/products/hw/switches/ps646/products_configuration_guide_chapter09186a00801cdf14.html#1053923

But I hope you have at least one router in your environment and it can operate as NTP master (server) and the other swithces as client.

Bye

FCS

Rate me if I helped.