Ensure internal information system clocks are synchronizing - GPS.


The Linux operating system must, for networked systems, synchronize clocks with a server that is synchronized to one of the redundant United States Naval Observatory (USNO) time servers, a time server designated for the appropriate DoD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS)


Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate.

Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network.

Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).

Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144


Edit the '/etc/ntp.conf' or '/etc/chrony.conf' file and add or update an entry to define 'maxpoll' to '10' as follows:

server 0.rhel.pool.ntp.org iburst maxpoll 10

If NTP was running and 'maxpoll' was updated, the NTP service must be restarted:

# systemctl restart ntpd

If NTP was not running, it must be started:

# systemctl start ntpd

If 'chronyd' was running and 'maxpoll' was updated, the service must be restarted:

# systemctl restart chronyd.service

If 'chronyd' was not running, it must be started:

# systemctl start chronyd.service

See Also


Item Details


References: 800-53|AU-8(1)(a), 800-53|AU-8(1)(b), CCI|CCI-001891, CCI|CCI-002046, CSCv6|6.1, CSCv7|6.1, Rule-ID|SV-204603r603261_rule, STIG-ID|RHEL-07-040500

Plugin: Unix

Control ID: 71d130ebc9d87d1169c41ebe98e7da47ea07c0e6f3e4ccd84c6fd9134e418bca