Chapter 5
Administering the Switch
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•
Note
You can disable NTP packets from being received on routed ports and VLAN interfaces. You cannot
disable NTP packets from being received on access ports. For details, see the
on a Specific Interface"
Configuration Guide, Release 12.4T.
For details about configuring NTPv4, see the
IPv6 Configuration Guide, Release
Configuring Time and Date Manually
If no other source of time is available, you can manually configure the time and date after the system is
restarted. The time remains accurate until the next system restart. We recommend that you use manual
configuration only as a last resort. If you have an outside source to which the switch can synchronize,
you do not need to manually set the system clock.
You must reset this setting if you have manually set the system clock and the stack master fails and
Note
different stack member resumes the role of stack master.
These sections contain this configuration information:
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•
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Setting the System Clock
If you have an outside source on the network that provides time services, such as an NTP server, you do
not need to manually set the system clock.
Beginning in privileged EXEC mode, follow these steps to set the system clock:
Command
Step 1
clock set hh:mm:ss day month year
or
clock set hh:mm:ss month day year
OL-26520-01
Improved security compared to NTPv3. The NTPv4 protocol provides a security framework based
on public key cryptography and standard X509 certificates.
Automatic calculation of the time-distribution hierarchy for a network. Using specific multicast
groups, NTPv4 automatically configures the hierarchy of the servers to achieve the best time
accuracy for the lowest bandwidth cost. This feature leverages site-local IPv6 multicast addresses.
section of the
Setting the System Clock, page 5-5
Displaying the Time and Date Configuration, page 5-6
Configuring the Time Zone, page 5-6
Configuring Summer Time (Daylight Saving Time), page 5-7
Purpose
Manually set the system clock using one of these formats.
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
"Implementing NTPv4 in IPv6"
"Implementing NTPv4 in IPv6"
12.4T.
For hh:mm:ss, specify the time in hours (24-hour format), minutes,
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and seconds. The time specified is relative to the configured time
zone.
For day, specify the day by date in the month.
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For month, specify the month by name.
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For year, specify the year (no abbreviation).
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Managing the System Time and Date
"Disabling NTPv4 Services
chapter of the
Cisco IOS IPv6
chapter of the
Cisco IOS
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