Purpose
Command or Action
Create an access group, and apply a basic IP access list..
[
no
]
ntp access-group
{
query-only
|
serve-only
|
serve
|
peer
}
access-list-number
Step 3
•
query-only
: NTP control queries.
Example:
•
serve-only
: Time requests.
Device(config)#
ntp access-group peer 99
•
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 access-list-number permit source
[
source-wildcard
]
Step 4
•
access-list-number
: IP access list number. The range
is from 1 to 99.
Example:
Device(config)#
access-list 99 permit 172.20.130.5
•
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.
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.
Note
Use the
no
form of this command to remove authentication
key.
Returns to privileged EXEC mode.
end
Example:
Step 5
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)
23
Administering the Device
Disabling NTP Services on a Specific Interface
