Setting the Time Zone
Problem
You want to change the time zone on the router.
Solution
To configure the router's local time zone, use the following configuration command:
Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#clock timezone EST 5 Router(config)#end Router#
The clock timezone configuration command accepts any freeform zone name (EST, PST, Eastern, etc.), followed by an offset from the UTC (24 to 24 hours) and an optional offset from UTC in minutes for areas that require it.
Discussion
By default, the router uses UTC, also called Coordinated Universal Time. UTC, formerly known as Greenwich Mean Time (GMT), has become the worldwide standard for time and date. The principles for calculating local time zones from UTC are the same as for GMT. The only difference is that UTC is based on precise atomic clocks, shortwave radio signals, and satellites to ensure accuracy, which need not actually be located in Greenwich, England.
It is useful to set the router's internal system clock to display the time in the local time zone. North American clocks set to UTC, for example, display the time between five and eight hours ahead of the local time. This means that somebody reading the clock has to do some mental arithmetic to translate to local time, which is sometimes awkward and makes correlating the times of network problems more difficult than it needs to be.
You can view the current time zone information with the show clock detail command:
Router>show clock detail 14:27:31.415 EST Sun Jan 29 2006 Time source is NTP Router>
Many organizations choose to configure all of their routers to the same time zone to ease problem correlation, regardless of router location. The network administrators will configure all of their routers to the same time zone, even if they are physically located in a different part of the world. We recommend doing this because it simplifies troubleshooting by eliminating the need to do a lot of mental arithmetic that can unnecessarily slow down an already difficult and stressful situation.
Table 14-1 shows the configuration for several of the most commonly used time zones in North America. A detailed list of worldwide time zones is located in Appendix B.
Time zone | Abbr. | Offset from UTC | Configuration command |
---|---|---|---|
Hawaiian Standard Time | HST | UTC -10 |
clock timezone HST 10 |
Alaska Standard Time | AKST | UTC -9 |
clock timezone AKST 9 |
Pacific Standard Time | PST | UTC -8 |
clock timezone PST 8 |
Mountain Standard Time | MST | UTC -7 |
clock timezone MST 7 |
Central Standard Time | CST | UTC -6 |
clock timezone CST 6 |
Eastern Standard Time | EST | UTC -5 |
clock timezone EST 5 |
Atlantic Standard Time | AST | UTC -4 |
clock timezone AST 4 |
Newfoundland Standard Time | NST | UTC -3.5 |
clock timezone NST 3 30 |
See Also
Recipe 14.4; Recipe 14.5; Appendix B