Cisco Router – Configuring Time Manually

Marty: You’re not gonna believe this. We have to go back to 1955
Doc: I don’t believe it!
Marty: That’s right, Doc. November 12th, 1955.
Doc: Unbelievable that Old Biff could’ve chosen that particular date. It could mean that that point in time inherently contains some sort of cosmic significance, almost as if it were the temporal junction point of the entire space-time continuum. On the other hand, it could just be an amazing coincidence.

– Back to the Future Part II
– Robert Zemeckis and Bob Gale

To view the system time on a router, use the show clock command:

DocBrown>en
Password:
DocBrown#show clock
*04:53:21.590 UTC Wed Mar 1 1993

The asterisk in front of the time indicates that the time value is not authoritative. A time of March 1 1993 is the default time value when you turn on a router that has neither NTP configured, nor a manually-configured time.

A show clock detail confirms that no time source has been configured:

DocBrown>en
Password:
DocBrown#show clock detail
*04:55:06.999 UTC Wed Mar 1 1993
No time source

To set up the system time manually, use clock timezone (to set the timezone) and the clock set (to set the time). Configure the timezone before you configure the time because any change from the default UTC timezone will also alter the system time, and you’ll have to reconfigure the time again. So, save a step and do the timezone first:

DocBrown#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
DocBrown(config)#clock timezone PST -8
DocBrown(config)#exit

DocBrown#clock set 22:04:00 12 November 1955
                                        ^
% Invalid input detected at '^' marker.

DocBrown#clock set 22:04:00 12 November ?
    Year

DocBrown#clock set 22:04:00 12 November 2015

Doc Brown cannot go back to 1965 because the acceptable range of values for year is 1993 to 2035. So, let’s send him to 2015 instead.

To verify, use the show clock command:

DocBrown#show clock
22:04:05.311 PST Thu Nov 12 2015

The asterisk in front of the time is gone now, indicating that the time value is authoritative.

Now show clock detail shows that it is a user-configured time:

DocBrown#sh clock detail
22:48:59.047 PST Thu Nov 12 2015
Time source is user configuration

Additional Information:

clock set command in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2

clock timezone command in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2

show clock command in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2

This entry was posted in geek, mecha, v4vendetta and tagged , , , , . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

2 Comments

  1. Posted June 3, 2016 at 5:55 am | Permalink

    I am really pleased to glance at this blog posts which consists of plenty of helpful facts,
    thanks for providing these kinds of data.

  2. Posted January 11, 2017 at 2:00 pm | Permalink

    I’m so much interested in CISCO networking and it’s the best description about CISCO router configuration manually for a newbie. Hey Jabbar, firstly thanks for the tutorial and I’ve a question with Packet Tracer in CISCO. As I Download Packet Tracer 7.0 in my PC and also running very easily with the help of NetAcad and I’m also trying to combine it with CISCO router. When I’ll complete the step of learning Packet Tracer. I’ll just inform you and ask you.
    Your Post is helping me lot. So I think I’ll be success and I’ll also inform you later about my progress in networking simulator to router as well.
    Thanks again 🙂

One Trackback

Post a Comment

Your email is never published nor shared. Required fields are marked *

You may use these HTML tags and attributes <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

*
*