Information
The loss of connectivity to a particular authoritative time source will result in the loss of time synchronization (free-run mode) and increasingly inaccurate time stamps on audit events and other functions.
Multiple time sources provide redundancy by including a secondary source. Time synchronization is usually a hierarchy; clients synchronize time to a local source while that source synchronizes its time to a more accurate source. The network device must utilize an authoritative time server and/or be configured to use redundant authoritative time sources. This requirement is related to the comparison done in CCI-001891.
DOD-approved solutions consist of a combination of a primary and secondary time source using a combination or multiple instances of the following: A time server designated for the appropriate DOD network (NIPRNet/SIPRNet); United States Naval Observatory (USNO) time servers; and/or the Global Positioning System (GPS). The secondary time source must be located in a different geographic region than the primary time source.
Solution
Configure the network device to synchronize internal information system clocks with the primary and secondary time sources.
set system ntp authentication-key 1 type sha256
set system ntp authentication-key 1 value 'PSK'
set system ntp authentication-key 2 type sha1
set system ntp authentication-key 2 value 'PSK'
set system ntp server <address 1> key 1
set system ntp server <address 1> prefer
set system ntp server <address 2> key 2
set system ntp trusted-key 1
set system ntp trusted-key 2
set system ntp source-address <lo0 or OOBM address>