2.2.1.3 Ensure ntp is configured - restrict -4

Information

ntp is a daemon which implements the Network Time Protocol (NTP). It 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.

Note: This recommendation only applies if ntp is in use on the system.

Rationale:

If ntp is in use on the system proper configuration is vital to ensuring time synchronization is working properly.

Solution

Add or edit restrict lines in /etc/ntp.conf to match the following:

restrict -4 default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

Add or edit server or pool lines to /etc/ntp.conf as appropriate:

server <remote-server>

Add or edit the OPTIONS in /etc/sysconfig/ntpd to include '-u ntp:ntp':

OPTIONS='-u ntp:ntp'

See Also

https://workbench.cisecurity.org/files/2925

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-8, CSCv7|6.1

Plugin: Unix

Control ID: d98383f89745504c7a4ab579d25b90aecc94c364e2cc75423c9b74f3c30dbefa