V-255612

Discussion

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.

Check Content

Review the device configuration.

The following command shows the configuration with an output modifier to display only NTP-related configuration:
show run | include ntp

Alternately, enter the command to display the configured NTP servers and whether or not NTP is enabled:
show ntp servers

If the output shows fewer than two configured NTP servers, this is a finding.

Ask the device administrator where the Primary NTP Server and Secondary NTP Server are located. 

If they are not in different geographic regions, this is a finding.