Cisco Catalyst 9200 Configuration Manual page 37

Administering the Device
Command or Action
Step 3 [no] ntp access-group {query-only | serve-only | serve |
peer} access-list-number
Example:
Device(config)# ntp access-group peer 99
Step 4
access-list access-list-number permit source
[source-wildcard]
Example:
Device(config)# access-list 99 permit 172.20.130.5
Step 5 end
Example:
Device(config)# end
Disabling NTP Services on a Specific Interface
To disable NTP packets from being received on an interface, perform this procedure:
System Management Configuration Guide, Cisco IOS XE Gibraltar 16.10.x (Catalyst 9200 Switches)
Disabling NTP Services on a Specific Interface
Purpose
Create an access group, and apply a basic IP access list..
• query-only: NTP control queries.
• serve-only: Time requests.
• serve: Allows time requests and NTP control queries,
but does not allow the device to synchronize to the
remote device.
• peer: Allows time requests and NTP control queries
and allows the device to synchronize to the remote
device.
• access-list-number: IP access list number. The range
is from 1 to 99.
Use the no form of this command to remove access control
to the switch NTP services.
Create the access list.
• access-list-number: IP access list number. The range
is from 1 to 99.
• permit: Permits access if the conditions are matched.
• source: IP address of the device that is permitted access
to the device.
• source-wildcard: Wildcard bits to be applied to the
source.
Note When creating an access list, remember that, by
default, the end of the access list contains an
implicit deny statement for everything if it did
not find a match before reaching the end.
Use the no form of this command to remove authentication
key.
Returns to privileged EXEC mode.
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