6.5 Configure Network Time Protocol (NTP) - restrict -6 default kod nomodify notrap nopeer noquery

Information

The Network Time Protocol (NTP) is designed to synchronize system clocks across a
variety of systems and use a source that is highly accurate. More information on NTP can be
found at http-//www.ntp.org. NTP can be configured to be a client and/or a server.

*Rationale*

It is recommended that physical systems and virtual guests lacking direct access to the
physical host's clock be configured as NTP clients to synchronize their clocks (especially to
support time sensitive security mechanisms like Kerberos). This also ensures log files have
consistent time records across the enterprise, which aids in forensic investigations.

Solution

Install ntp-# apt-get install ntp
Ensure the following lines are in /etc/ntp.conf-
restrict -4 default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

Also, make sure /etc/ntp.conf has at least one NTP server specified-server <ntp-server>
Note- <ntp-server> is the IP address or hostname of a trusted time server. Configuring an
NTP server is outside the scope of this benchmark.

See Also

https://workbench.cisecurity.org/files/91

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CSCv6|3.1

Plugin: Unix

Control ID: e2682519c15f982c96a2d268285d32346e55febc5b95be5f2bce466f6aa6d5ed