Reference Guide

To display the system clock state with respect to NTP, use the show ntp status command from EXEC Privilege mode.
R6(conf)#do show ntp status
Clock is synchronized, stratum 2, reference is 192.168.1.1
frequency is -369.623 ppm, stability is 53.319 ppm, precision is 4294967279
reference time is CD63BCC2.0CBBD000 (16:54:26.049 UTC Thu Mar 12 2009)
clock offset is 997.529984 msec, root delay is 0.00098 sec
root dispersion is 10.04271 sec, peer dispersion is 10032.715 msec
peer mode is client
To display the calculated NTP synchronization variables received from the server that the system uses to synchronize its clock,
use the show ntp associations command from EXEC Privilege mode.
R6(conf)#do show ntp associations
remote ref clock st when poll reach delay offset disp
==========================================================
#192.168.1.1 .LOCL. 1 16 16 76 0.98 -2.470 879.23
* master (synced), # master (unsynced), + selected, - candidate
Configuring NTP Broadcasts
The switch can receive broadcasts of time information.
You can set interfaces within the system to receive NTP information through broadcast.
To configure an interface to receive NTP broadcasts, use the following commands.
● Set the interface to receive NTP packets.
INTERFACE mode
ntp broadcast client
2w1d11h : NTP: Maximum Slew:-0.000470, Remainder = -0.496884
Disabling NTP on an Interface
By default, NTP is enabled on all active interfaces. If you disable NTP on an interface, the system drops any NTP packets sent
to that interface.
To disable NTP on an interface, use the following command.
● Disable NTP on the interface.
INTERFACE mode
ntp disable
To view whether NTP is configured on the interface, use the show config command in INTERFACE mode. If ntp disable
is not listed in the show config command output, NTP is enabled. (The show config command displays only non-default
configuration information.)
Configuring a Source IP Address for NTP Packets
By default, the source address of NTP packets is the IP address of the interface used to reach the network.
You can configure one interface’s IP address include in all NTP packets.
To configure an IP address as the source address of NTP packets, use the following command.
● Configure a source IP address for NTP packets.
CONFIGURATION mode
ntp source interface
Enter the following keywords and slot/port or number information:
○ For a loopback interface, enter the keyword loopback then a number between 0 and 16383.
○ For a port channel interface, enter the keyword lag then a number from 1 to 255.
System Time and Date
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