How to configure Network Time Protocol in Cisco ASA
Cisco ASA provides support for the Network Time Protocol (NTP) to synchronize the system clock with an NTP server. The device administrator does not need to update the system clock manually because the security appliance overrides the manual clock setting when it synchronizes the time with the NTP server. Setting up an NTP server is important when an organization uses certificates (PKI) to authenticate users and devices on the network.
NTP is set up by using the ntp commands, as shown in the following command syntaxes:
ntp server ip_address [key key_id] [source interface_name] [prefer] ntp authenticate ntp authentication-key key_id md5 md5_key ntp trusted-key key_id