Configuring The Source Ip Address For Ntp Packets - Cisco Aironet 1100 Series Installation And Configuration Manual

Chapter 6 Administering the Access Point
If the source IP address matches the access lists for more than one access type, the first type is granted.
If no access groups are specified, all access types are granted to all devices. If any access groups are
specified, only the specified access types are granted.
To remove access control to the access point NTP services, use the no ntp access-group {query-only |
serve-only | serve | peer} global configuration command.
This example shows how to configure the access point to allow itself to synchronize to a peer from access
list 99. However, the access point restricts access to allow only time requests from access list 42:
AP# configure terminal
AP(config)# ntp access-group peer 99
AP(config)# ntp access-group serve-only 42
AP(config)# access-list 99 permit 172.20.130.5
AP(config)# access list 42 permit 172.20.130.6
Disabling NTP Services on a Specific Interface
NTP services are enabled on all interfaces by default.
Beginning in privileged EXEC mode, follow these steps to disable NTP packets from being received on
an interface:
Command
Step 1 configure terminal
Step 2
interface interface-id
Step 3 ntp disable
Step 4 end
Step 5
show running-config
Step 6 copy running-config startup-config
To re-enable receipt of NTP packets on an interface, use the no ntp disable interface configuration
command.

Configuring the Source IP Address for NTP Packets

When the access point sends an NTP packet, the source IP address is normally set to the address of the
interface through which the NTP packet is sent. Use the ntp source global configuration command when you
want to use a particular source IP address for all NTP packets. The address is taken from the specified
interface. This command is useful if the address on an interface cannot be used as the destination for reply
packets.
OL-2851-01
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the interface to disable.
Disable NTP packets from being received on the interface.
By default, all interfaces receive NTP packets.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Cisco Aironet 1100 Series Access Point Installation and Configuration Guide
Managing the System Time and Date
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