[src/trunk]: src/etc Attempt to improve comments about how to choose servers,

[apb <apb%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ccc4159d4d31
branches:  trunk
changeset: 325783:ccc4159d4d31
user:      apb <apb%NetBSD.org@localhost>
date:      Mon Jan 06 11:25:03 2014 +0000

description:
Attempt to improve comments about how to choose servers,
and about what "tos minsane" does.

diffstat:

 etc/ntp.conf |  39 +++++++++++++++++++++------------------
 1 files changed, 21 insertions(+), 18 deletions(-)

diffs (68 lines):

diff -r c0533d4773c2 -r ccc4159d4d31 etc/ntp.conf
--- a/etc/ntp.conf      Mon Jan 06 11:21:34 2014 +0000
+++ b/etc/ntp.conf      Mon Jan 06 11:25:03 2014 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: ntp.conf,v 1.16 2014/01/06 11:21:34 apb Exp $
+# $NetBSD: ntp.conf,v 1.17 2014/01/06 11:25:03 apb Exp $
 #
 # NetBSD default Network Time Protocol (NTP) configuration file for ntpd
 
@@ -23,7 +23,8 @@
 
 logconfig      -syncstatus
 
-# This will help minimize disruptions due to network congestion. Don't
+# 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
@@ -77,21 +78,18 @@
 restrict ::1
 
 # Hereafter should be "server" or "peer" statements to configure other
-# hosts to exchange NTP packets with. Peers should be selected in such
-# a way that the network path to them is 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. NTP assumes such symmetry in its network delay
-# calculation. NTP will apply an incorrect adjustment to timestamps
-# received from the peer if the path is not symmetric. This can result
-# in clock skew (your system clock being maintained consistently wrong
-# by a certain amount).
+# 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.
 #
-# The best way to select symmetric peers is to make sure that the
-# network path to them is as short as possible (this reduces the chance
-# that there is more than one network path between you and your peer).
-# You can measure these distances with the traceroute(8)  program. The
-# best place to start looking for NTP peers for your system is within
-# your own network, or at your Internet Service Provider (ISP).
+# Peers 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.
@@ -104,8 +102,13 @@
 #server                an.ntp.server.goes.here
 #restrict      an.ntp.server.goes.here nomodify notrap
 
-# Public servers from the pool.ntp.org project. Volunteer's servers
-# are dynamically assigned to the CNAMES below via DNS round-robin.
+# 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, but
+# servers that are closer to you are likely to be better.  Consider
+# using servers specific to your country, a nearby country, or your
+# continent.
+#
 # 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: