Use the Cisco IOS EXEC command show clock to view a device’s software clock. Append detail to display how the device learned its current date and time, including whether the time is authoritative. section 2.1.2 section 2.4
R1# show clock detail *08:56:18.831 UTC Mon Aug 28 2023 #1 Time source is hardware calendar #2 #1 The asterisk (*) indicates that the time is not authoritative. #2 R1 learned the date and time from its hardware calendar.
The annotated output identifies an unauthoritative clock with an asterisk and shows when the software clock learned time from the hardware calendar. section 2.1.2
Interpret the command output alongside related clock operations:
- A leading asterisk means the displayed time is not authoritative; it disappears after the time is set. section 2.1.2
- The normal output uses UTC by default; clock timezone changes the displayed time zone in global configuration mode. section 2.1.2 section 2.4
- Use show calendar to inspect a separate hardware clock, and use clock read-calendar or clock update-calendar for one-time synchronization. section 2.1.2
