ntpd 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.
To ensure that ntpd implements correct server restrictions, make sure that the following lines exist in the file /etc/ntpd.conf:
restrict -4 default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
This recommendation only applies if ntp is in use on the system.