xref: /src/etc/ntp.conf

# $NetBSD: ntp.conf,v 1.23 2021/10/28 07:24:40 kim Exp $
#
# NetBSD default Network Time Protocol (NTP) configuration file for ntpd

# This file is intended to be both a usable default, and a Quick-Start
# Guide. The directives and options listed here are not at all complete.
# A great deal of additional documentation, including links to FAQS and
# other guides, may be found on the official NTP web site, in particular
#
#	http://www.ntp.org/documentation.html

# Process ID file, so that the daemon can be signalled from scripts

pidfile /var/run/ntpd.pid

# Don't give up even if the reference time is hugely different. This can
# happen if the system was suspended and resumed.

#tinker panic 0

# The correction calculated by ntpd(8) for the local system clock's
# drift is stored here.

driftfile /var/db/ntp.drift

# Suppress the syslog(3) message for each peer synchronization change.

logconfig -syncstatus

# Refuse to set the local clock if there are too few good peers or servers.
# This may help minimize disruptions due to network congestion. Don't
# do this if you configure only one server!

tos minsane 2

# 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 consistent time.

tos minclock 3 maxclock 6

# Set the number of tries to register with mdns. 0 means never

mdnstries 0

# New ntpd disables the ntpdc protocol by default, to re-enable uncomment
# the following line

#enable mode7

# Allow hasty ntpdate clients to avoid rate limiting / kod responses.
# The default is 2 seconds between packets from the client.

#discard minimum 1

# Access control restrictions.
# See /usr/share/doc/html/ntp/accopt.html for syntax.
# See <http://support.ntp.org/bin/view/Support/AccessRestrictions> for advice.
# Last match wins.
#
# Some of the more common keywords are:
#   ignore      Deny packets of all kinds.
#   limited     Deny time service if the packet violates the rate limits
#               established by the discard command. Does not affect ntpq or
#               ntpdc queries.
#   kod         Send "kiss-o'-death" packets if clients exceed rate limits.
#               No effect without the limited flag.
#   nomodify    Deny attempts to modify the state of the server via ntpq or
#               ntpdc queries.
#   noquery     Deny all ntpq and ntpdc queries.  Does not affect time
#               synchronisation.
#   nopeer      Prevent establishing new peer associations.
#               Does not affect peers configured using "peer" lines.
#               Does not affect client/server time synchronisation.
#   noserve     Deny all time synchronisation.  Does not affect ntpq or
#               ntpdc queries.
#   notrap      Deny the trap subset of the ntpdc control message protocol.
#   notrust     Deny packets that are not cryptographically authenticated.
#
# By default, allow client/server time exchange without prior
# arrangement, but deny configuration changes, queries, and peer
# associations that were not explicitly configured.

restrict default limited kod nomodify notrap nopeer noquery

# Restrictions used for associations (peer, server, pool).

restrict source nomodify notrap noquery

# Fewer restrictions for the local subnet.
# (Uncomment and adjust as appropriate.)

#restrict 192.0.2.0 mask 255.255.255.0 limited kod nomodify notrap nopeer
#restrict 2001:db8:: mask ffff:ffff::  limited kod nomodify notrap nopeer

# No restrictions for localhost.

restrict 127.0.0.1
restrict ::1

# Hereafter should be "server", "peer", or "pool" statements to configure
# other hosts to exchange NTP packets with.
#
# See <http://support.ntp.org/bin/view/Support/DesigningYourNTPNetwork>
# and <http://support.ntp.org/bin/view/Support/SelectingOffsiteNTPServers>
# for advice.
#
# Peers or servers should be selected in such a way that the network
# path to them is short, uncongested, and symmetric (that is, the series
# of links and routers used to get to the peer is the same one that
# the peer uses to get back).  The best place to start looking for NTP
# peers for your system is within your own network, or at your Internet
# Service Provider (ISP).
#
# Ideally, you should select at least three other systems to talk NTP
# with, for an "what I tell you three times is true" effect.

#peer an.ntp.peer.goes.here iburst
#server an.ntp.server.goes.here iburst

# The pool.ntp.org project coordinates public time servers provided by
# volunteers.  See <http://www.pool.ntp.org>.  The *.netbsd.pool.ntp.org
# servers are intended to be used by default on NetBSD hosts.
#
# 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.
# The "2" host is used to obtain both IPv4 and IPv6 addresses.
#
# The pool.ntp.org project needs more volunteers! The only criteria to
# join are a nailed-up connection and a static IP address. For details,
# see the web page <http://www.pool.ntp.org/join.html>

pool 2.netbsd.pool.ntp.org iburst