Creating NTP Restrict Entries

Note

DEMO FEATURE - NTPv4 Restrict is a demonstration feature on some products. Demonstration features are provided for testing purposes. Demonstration features are for lab use only and are not for use in a production environment. For more information on feature support, see VOSS Feature Support Matrix.

Perform the following procedure to configure the NTP restrict capability for a specific IPv4 or IPv6 address(es), which means the switch permits NTP traffic flow from the specified IP addresses only. By default the NTP restrict capability is disabled.

Note

• You can configure a maximum of 128 NTP Restrict entries (IPv4 or IPv6 addresses).

• 0.0.0.0/0 or ::/0 NTP restrict entries are equivalent to no NTP restrict rules configured.

1. Enter Global Configuration mode:

   enable

   configure terminal

2. Configure a specific NTP restrict IP address:

   ntp restrict WORD<0-255>

3. Verify the restricted IP address:

   show ntp restrict

Example

Switch:1>enable
Switch:1#configure terminal
Switch:1(config)#ntp restrict 192.0.0.0
Switch:1(config)#show ntp restrict
================================================================================
                            NTP Restrict Information
================================================================================
TYPE     ADDRESS                                    MASK/PREFIX LEN
--------------------------------------------------------------------------------
IPv4     192.0.0.0                                    23
--------------------------------------------------------------------------------