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NTP server sync - question

Hi There,

I'm having a problem with the ntp time passed on to a number of routers/switches in the LAN after day light saving started two weeks ago here in sydney.

The following is the configuration and the time on the router acting as ntp server,

router LAN IP address: 10.1.1.253

ntp clock-period 17208294

ntp server 129.127.40.3

ntp server 129.127.28.4 prefer

rt#sh clock detail

17:49:37.407 AEST Mon Oct 20 2008

Time source is NTP

Summer time starts 03:00:00 AEDT Sun Oct 5 2008

Summer time ends 03:00:00 AEST Sun Apr 5 2009

This is the configuration on the router, which time is incorrect,

ntp clock-period 17180360

ntp source Vlan100

ntp server 10.1.1.253

!

rt1#sh clock detail

16:50:27.538 AEST Mon Oct 20 2008

Time source is NTP

Summer time starts 02:00:00 AEST Sun Oct 26 2008

Summer time ends 02:00:00 AEST Sun Mar 29 2009

As you can notice the switch with the incorrect switch is one hour behind now.

Can any help or point me in the right direction as how can i get the time synchronised between the two?

Cheers,

Esteban

2 ACCEPTED SOLUTIONS

Accepted Solutions
Gold

Re: NTP server sync - question

As you see from show clock detail your summer times are different and because today is 20th Oct on one only one device is summer time

check in you run configuration

clock timezone

clock summer-time

Those should match on both devices

M.

Hall of Fame Super Gold

Re: NTP server sync - question

Esteban

As M. points out the issue here is really not with NTP but is with the adjustment for daylight savings which is done by the local device. NTP always passes the time in UTC (GMT) and the local device makes the adjustments to Universal Coordinated Time to fit the local situation.

The issue really is that the devices are running different versions of code, and that Cisco made a change in the dates for the implementation of daylight savings time. The solution to your issue (until you can get both devices running the same version of code) is that there is an optional set of parameters in the clock summer-time command in which you can specify what dates the device should use. So you can get the incorrect device to use the same dates as the correct device and then they both will be the same.

HTH

Rick

4 REPLIES
Gold

Re: NTP server sync - question

As you see from show clock detail your summer times are different and because today is 20th Oct on one only one device is summer time

check in you run configuration

clock timezone

clock summer-time

Those should match on both devices

M.

Hall of Fame Super Gold

Re: NTP server sync - question

Esteban

As M. points out the issue here is really not with NTP but is with the adjustment for daylight savings which is done by the local device. NTP always passes the time in UTC (GMT) and the local device makes the adjustments to Universal Coordinated Time to fit the local situation.

The issue really is that the devices are running different versions of code, and that Cisco made a change in the dates for the implementation of daylight savings time. The solution to your issue (until you can get both devices running the same version of code) is that there is an optional set of parameters in the clock summer-time command in which you can specify what dates the device should use. So you can get the incorrect device to use the same dates as the correct device and then they both will be the same.

HTH

Rick

New Member

Re: NTP server sync - question

Thanks to both! extremelly helpful

It was indeed due to the adjustments for daylight savings over here. Once i changed the dates the time was changed to show the correct one.

Thanks heaps once again,

Esteban

Hall of Fame Super Gold

Re: NTP server sync - question

Esteban

I am glad that our answers helped you to resolve your issue. Thank you for using the rating system to indicate that your issue was resolved (and thanks for the rating). It makes the forum mor useful when people can read about an issue and can know that responses did lead to resolution of the issue.

The forum is an excellent place to learn about Cisco networking. I encourage you to continue your participation in the forum.

HTH

Rick

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