HardenedBSD/etc/ntp.conf

#
# $FreeBSD$
#
# Default NTP servers for the FreeBSD operating system.
#
# Don't forget to enable ntpd in /etc/rc.conf with:
# ntpd_enable="YES"
#
# The driftfile is by default /var/db/ntpd.drift, check
# /etc/defaults/rc.conf on how to change the location.
#

#
# The following three servers will give you a random set of three
# NTP servers geographically close to you.
# See http://www.pool.ntp.org/ for details. Note, the pool encourages
# users with a static IP and good upstream NTP servers to add a server
# to the pool. See http://www.pool.ntp.org/join.html if you are interested.
#
# The option `iburst' is used for faster initial synchronization.
#
server 0.freebsd.pool.ntp.org iburst
server 1.freebsd.pool.ntp.org iburst
server 2.freebsd.pool.ntp.org iburst
#server 3.freebsd.pool.ntp.org iburst

#
# If you want to pick yourself which country's public NTP server
# you want sync against, comment out the above servers, uncomment
# the next ones and replace CC with the country's abbreviation.
# Make sure that the hostnames resolve to a proper IP address!
#
# server 0.CC.pool.ntp.org iburst
# server 1.CC.pool.ntp.org iburst
# server 2.CC.pool.ntp.org iburst

#
# Security:
#
# By default, only allow time queries and block all other requests
# from unauthenticated clients.
#
# See http://support.ntp.org/bin/view/Support/AccessRestrictions
# for more information.
#
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
#
# Alternatively, the following rules would block all unauthorized access.
#
#restrict default ignore
#restrict -6 default ignore
#
# In this case, all remote NTP time servers also need to be explicitly
# allowed or they would not be able to exchange time information with
# this server.
#
# Please note that this example doesn't work for the servers in
# the pool.ntp.org domain since they return multiple A records.
#
#restrict 0.pool.ntp.org nomodify nopeer noquery notrap
#restrict 1.pool.ntp.org nomodify nopeer noquery notrap
#restrict 2.pool.ntp.org nomodify nopeer noquery notrap
#
# The following settings allow unrestricted access from the localhost
restrict 127.0.0.1
restrict -6 ::1
restrict 127.127.1.0

#
# If a server loses sync with all upstream servers, NTP clients
# no longer follow that server. The local clock can be configured
# to provide a time source when this happens, but it should usually
# be configured on just one server on a network. For more details see
# http://support.ntp.org/bin/view/Support/UndisciplinedLocalClock
# The use of Orphan Mode may be preferable.
#
#server 127.127.1.0
#fudge 127.127.1.0 stratum 10