Cisco 2950 - Catalyst Switch - Configuring NTP Access Restrictions

8-8
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 8 Administering the Switch
Managing the System Time and Date
Beginning in privileged EXEC mode, follow these steps to configure the switch to receive NTP broadcast
packets from connected peers:
To disable an interface from receiving NTP broadcast packets, use the no ntp broadcast client interface
configuration command. To change the estimated round-trip delay to the default, use the no ntp
broadcastdelay global configuration command.
This example shows how to configure a port to receive NTP broadcast packets:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ntp broadcast client
Configuring NTP Access Restrictions
You can control NTP access on two levels as described in these sections:
• Creating an Access Group and Assigning a Basic IP Access List, page 8-9
• Disabling NTP Services on a Specific Interface, page 8-10
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Specify the interface to receive NTP broadcast packets, and enter interface
configuration mode.
Step 3
ntp broadcast client Enable the interface to receive NTP broadcast packets.
By default, no interfaces receive NTP broadcast packets.
Step 4
exit Return to global configuration mode.
Step 5
ntp broadcastdelay microseconds (Optional) Change the estimated round-trip delay between the switch and
the NTP broadcast server.
The default is 3000 microseconds; the range is 1 to 999999.
Step 6
end Return to privileged EXEC mode.
Step 7
show running-config Verify your entries.
Step 8
copy running-config startup-config (Optional) Save your entries in the configuration file.