Ntp server

Installation

• apt install ntp

Die Hauptkonfiguration vom NTP Server

# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift

# Leap seconds definition provided by tzdata
leapfile /usr/share/zoneinfo/leap-seconds.list

# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable

#server: Ähnlich wie pool, nur das hier nur ein Server angegeben wird.
#server ntp.your-provider.example

#pool: Für Adressen des Typs  mobilisiert dieser Befehl eine dauerhafte Zuordnung im Client-Modus
#mit einer Reihe von Remote-Servern. In diesem Modus kann die lokale Uhr mit dem entfernten Server
#synchronisiert werden, aber der entfernte Server kann niemals mit dem lokalen synchronisiert werden
             
pool 0.debian.pool.ntp.org iburst
pool 1.debian.pool.ntp.org iburst
pool 2.debian.pool.ntp.org iburst
pool 3.debian.pool.ntp.org iburst


# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery limited
restrict -6 default kod notrap nomodify nopeer noquery limited

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1

# Needed for adding pool entries
restrict source notrap nomodify noquery

# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust


# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 192.168.123.255

# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines.  Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient

Statistiken anzeigen

• watch -n 1 ntpq -p

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 0.debian.pool.n .POOL.          16 p    -   64    0    0.000   +0.000   0.000
 1.debian.pool.n .POOL.          16 p    -   64    0    0.000   +0.000   0.000
 2.debian.pool.n .POOL.          16 p    -   64    0    0.000   +0.000   0.000
 3.debian.pool.n .POOL.          16 p    -   64    0    0.000   +0.000   0.000
+x.ns.gin.ntt.ne 129.250.35.222   2 u   43   64  377   30.994   +4.343   6.664
*ntp0.rrze.uni-e .GPS.            1 u   49   64  377   33.502   +2.076   7.938
+ntp2.lwlcom.net .GPS.            1 u   52   64  377   45.357   +5.363  10.198
+pmg.jonasled.de 131.188.3.220    2 u   52   64  377   40.279   +5.072  15.165
+h2954360.strato 208.90.67.116    3 u   46   64  377   49.506   +5.910   9.933
+sv1.ggsrv.de    192.53.103.103   2 u   50   64  377   37.064   +3.896   8.377
+static.255.156. 124.216.164.14   2 u   46   64  377   42.464   +6.099   9.968
+ntp1.m-online.n 212.18.1.106     2 u   47   64  377   34.221   +1.075   6.425
+stratum2-3.NTP. 129.70.137.82    2 u   36   64  377   42.527   +2.333   7.465
#ntp1.as213151.n 216.239.35.0     2 u   37   64  377   32.346  -56.093  78.495
+kuehlich.com    131.188.3.221    2 u   46   64  377   49.752   +4.470  10.315
+tanss.it-risch. 192.53.103.103   2 u   45   64  377   28.801   -0.441   5.282

Quellen

• https://dokuwiki.nausch.org/doku.php/centos:ntp-zeitserver