ntp example config

#
# $FreeBSD: stable/12/usr.sbin/ntp/ntpd/ntp.conf 337649 2018-08-11 17:42:42Z brd $
#
# 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.
#

#
# Set the target and limit for adding servers configured via pool statements
# or discovered dynamically via mechanisms such as broadcast and manycast.
# Ntpd automatically adds maxclock-1 servers from configured pools, and may
# add as many as maxclock*2 if necessary to ensure that at least minclock 
# servers are providing good consistant time.
#
tos minclock 3 maxclock 6

#
# The following pool statement will give you a random set of NTP servers
# geographically close to you.  A single pool statement adds multiple
# servers from the pool, according to the tos minclock/maxclock targets.
# See http://www.pool.ntp.org/ for details.  Note, pool.ntp.org 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.
#
#pool 0.freebsd.pool.ntp.org iburst

server time.fu-berlin.de iburst
server zeit.fu-berlin.de iburst
server ntp1.de-cix.net
server ntp2.de-cix.net
server ntp0.rrze.uni-erlangen.de
server ntp1.rrze.uni-erlangen.de
server ntp2.rrze.uni-erlangen.de
server ntp3.rrze.uni-erlangen.de
server ptbtime1.ptb.de
server ptbtime2.ptb.de
server ntps1-0.cs.tu-berlin.de
server ntps1-1.cs.tu-berlin.de
server ntp0.ewetel.de
server ntp1.ewetel.de
server dus2-ntp.mcbone.net.
server dus2-ntp2.mcbone.net.
server usno.hpl.hp.com
server ntp11.metas.ch
server ntp12.metas.ch
server ntps1-1.eecsit.tu-berlin.de
server 130.149.17.21 noselect
server 193.67.79.202 noselect
server 134.34.3.18 noselect
server ntp1.inrim.it noselect
server ntp2.inrim.it noselect
server 18.7.21.64 noselect
server 204.9.54.119 noselect
server 192.12.19.20 noselect
server 69.36.224.15 noselect
server mrobelix.de
server mail.madavi.de
#

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

#
# To configure a specific server, such as an organization-wide local
# server, add lines similar to the following.  One or more specific
# servers can be configured in addition to, or instead of, any server
# pools specified above.  When both are configured, ntpd first adds all
# the specific servers, then adds servers from the pool until the tos
# minclock/maxclock targets are met.
#
#server time.my-internal.org iburst

#
# Security:
#
# By default, only allow time queries and block all other requests
# from unauthenticated clients.
#
# The "restrict source" line allows peers to be mobilized when added by
# ntpd from a pool, but does not enable mobilizing a new peer association
# by other dynamic means (broadcast, manycast, ntpq commands, etc).
#
# See http://support.ntp.org/bin/view/Support/AccessRestrictions
# for more information.
#
restrict default limited kod nomodify notrap noquery nopeer
restrict source  limited kod nomodify notrap noquery

#
# Alternatively, the following rules would block all unauthorized access.
#
#restrict 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 ::1

#
# 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

# See http://support.ntp.org/bin/view/Support/ConfiguringNTP#Section_6.14.
# for documentation regarding leapfile. Updates to the file can be obtained
# from ftp://time.nist.gov/pub/ or ftp://tycho.usno.navy.mil/pub/ntp/.
# Use either leapfile in /etc/ntp or periodically updated leapfile in /var/db.
#leapfile "/etc/ntp/leap-seconds"
leapfile "/var/db/ntpd.leap-seconds.list"