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.
Satisfies: SRG-APP-000373-NDM-000298, SRG-APP-000374-NDM-000299, SRG-APP-000375-NDM-000300, SRG-APP-000395-NDM-000347
Solution
Configure the Arista network device for at least two trusted time sources and to use cryptographic authentication with the following command example:
switch#config
switch(config)#ntp authentication-key 12 sha1 0 <key>
switch(config)#ntp trusted-key 12
switch(config)#ntp authenticate servers
switch(config)#ntp local-interface Management1
switch(config)#ntp server 192.168.16.36 prefer key 12
switch(config)#ntp server 192.168.16.37 key 12
switch(config)#exit
Configure the local time zone for the device.
switch#config
switch(config)#clock timezone <timezone>
switch(config)#exit