CASA-ND-000940 - The Cisco ASA must be configured to synchronize its clock with the primary and secondary time sources using redundant authoritative time sources - ntp server prefer


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.


Configure the Cisco ASA to synchronize its clock with redundant authoritative time sources as shown in the example below.

ASA(config)# ntp server prefer
ASA(config)# ntp server
ASA(config)# end

See Also

Item Details


References: 800-53|AU-8(2), 800-53|AU-8b., CAT|II, CCI|CCI-001890, CCI|CCI-001893, Rule-ID|SV-239924r891333_rule, STIG-ID|CASA-ND-000940, Vuln-ID|V-239924

Plugin: Cisco

Control ID: 8b8f4033f654c412a0242ab8275cce67c8f45bb9e062bbfd2f91ea0c89bd1104