Cisco 2821 Clock Set Problem

[Aliz_ba123]

Hi dears

I have a problem with Cisco2821, I have 3 router Cisco2821

I want to set the correct clock on them, I run the "clock set xx:xx:xx Aug yy 2012",

Then wr and then reload the device

When the router comes up I enter "show clock" command.

The device show the previous time and it doesn’t change!

I don’t want to set NTP server.

Can anyone help me please?

Regards

[Leo Laohoo]

I don’t want to set NTP server.
Can anyone help me please?

NTP/SNTP is the way to go.  If you don't want to set NTP/SNTP then the only method is to manually configure the time and date every reboot.

You also need to reconfigure the time in case the clock goes either too fast or too slow.

[Aliz_ba123]

Dear leolaohoo

Thank you for answer but I have Cisco2811 and ..., and they don't have this problem,

I can set the clock on them and do reboot, then they have the correct time. And I have no NTP/SNTP.

I think this error is about my IOS or device hardware.

If you have any other solution please guide me

[Leo Laohoo]

Thank you for answer but I have Cisco2811 and ..., and they don't have this problem,

Maybe because you've configured "update calendar".  But even that is not accurate.

Remember that Cisco appliances do NOT have a dedicated clock/time mechanism.  They depend entirely on outside source.

[Joseph W. Doherty]

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Posting

Normally, the device's clock loses it time when device is rebooted (or power cycled).

Some devices also have a "calendar" which retains time across reboots (and power cycles too).

For those devices that have a "calendar", clock resets itself to calendar's current time.

Besides setting clock to current time, reset you calendar to current time too (i.e. "calendar set ...").

[brian.davis]

You can use an externam NTP server if the routers have access to the internet.  Just sayin... 

http://support.ntp.org/bin/view/Servers/NTPPoolServers