Information
Enable NTP authentication.
Rationale:
Using authenticated NTP ensures the Cisco device only permits time updates from authorized NTP servers.
Solution
Configure NTP authentication:
hostname(config)#ntp authenticate
Impact:
Organizations should establish three Network Time Protocol (NTP) hosts to set consistent time across the enterprise. Enabling the 'ntp authenticate' command enforces authentication between NTP hosts.
Default Value:
NTP authentication is not enabled.
References:
http://www.cisco.com/en/US/docs/ios-xml/ios/bsm/command/bsm-cr-n1.html#GUID-8BEBDAF4-6D03-4C3E-B8D6-6BCBC7D0F324