I don’t know about you but I like having the right time in my Cisco routers and/or switches. Having the right time is important especially when you need to find time sensitive information like when did a certain interface went down or did the router’s ACL block a certain traffic at a specific time. A lot of organizations have NTP servers that are stratum 1. Companies such as EndRun Technologies sell stratum 1 NTP servers which are normally synchronized over GPS, CDMA, or WWV. That being said, take advantage of that NTP server and point all of your nodes that are capable of running NTP to that server.
The issue that I have with Cisco routers/switches is that they default to UTC and even if you have a stratum 1 NTP server, when you issue show clock it will still show you the UTC time. I may be wrong to assume that not a lot of people know their UTC offset value for their timezone so when they see that UTC time, they’ll most likely go to Google and do a search. Fortunately, Cisco routers and switches have the capability of changing the UTC offset value. Now, you do not have to “google” the UTC equivalent for your timezone. Without further ado, here are the commands that you need to issue to change your Cisco router/switch’s timezone.
Router#sho clock 23:32:28.465 UTC Wed Jul 1 2012 Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router (config)#clock timezone PST -8 Router (config)#do show clock 15:33:06.549 PST Wed Jul 1 2012 Router (config)#clock summer-time PST recurring 2 Sun Mar 2:00 1 Sun Nov 2:00 Router (config)#do sho clock 16:34:15.462 PST Wed Jul 1 2012
Since my timezone is Pacific Standard Time (PST), I used -8 for my UTC offset value. Obviously, you need to change the offset value that is equivalent to your area’s timezone. The second command below is for countries that observe Daylight Savings Time (DST) rule. The new DST rule (2007 changes) observed here in the USA is that it begins at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November.
Now that you know how to change the timezone in Cisco IOS, it’s time for you to send out the changes to all of your routers and switches.
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