Loading ...As we all know, 2007 brings a change to the daylight savings time rules. DST will now start on the second Sunday in March and continue until the first Sunday in November. Unfortunatley, using NTP does not resolve this issue because NTP does not carry time zone or summertime information. So to facilitate this change, and to make sure times on network devices remain correct, changes have to be made. On a Cisco device with IOS, there are 2 ways to do this. The first one is to download the patch from Cisco and upgrade the OS. This can be a pain, but there is a simpler way to accomplish this, the clock summer-time command.
Log into the IOS device and enable.
IOSDevice# config t
IOSDevice(config)# clock summer-time CDT recurring 2 Sunday March 02:00 1 Sunday November 02:00 60
IOSDevice(config)# exit
IOSDevice(config)# clock summer-time CDT recurring 2 Sunday March 02:00 1 Sunday November 02:00 60
IOSDevice(config)# exit
Check the results.
IOSDevice# sh clock detail
Output:
IOSDevice# sh clock detail
12:57:35.142 CST Thu Feb 22 2007
Time source is NTP
Summer time starts 02:00:00 CST Sun Mar 11 2007
Summer time ends 02:00:00 CDT Sun Nov 4 2007
12:57:35.142 CST Thu Feb 22 2007
Time source is NTP
Summer time starts 02:00:00 CST Sun Mar 11 2007
Summer time ends 02:00:00 CDT Sun Nov 4 2007
Now everything is ready for the DST change!
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