OpenNTPD
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OpenNTPD is a lightweight NTP server ported from OpenBSD.
Installation
USE flags
USE flags for net-misc/openntpd Lightweight NTP server ported from OpenBSD
constraints
|
Enable HTTPS TLS time constraint support |
selinux
|
!!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur |
Emerge
Install OpenNTPD:
root #emerge --ask net-misc/openntpdService
To ask OpenNTPD to attempt clock sync on startup, edit /etc/conf.d/ntpd:
FILE
/etc/conf.d/ntpdGentoo OpenNTPD configuration file# See ntpd(8) man page ... some popular options:
# -s Set the time immediately at startup
# (Note: may cause up to a 15 second startup delay
# if ntp servers not reachable)
NTPD_OPTS="-s"
Note that if the clock drift is sufficiently large, you may first need to set the time manually using date(1).
OpenRC
Start the ntp daemon:
root #/etc/init.d/ntpd startAdd the ntp daemon to the default runlevel:
root #rc-update add ntpd defaultsystemd
To enable and start the service now:
root #systemctl enable --now ntpdConfiguration
The default configuration file for OpenNTPD:
FILE
/etc/ntpd.confGentoo's default configuration# Addresses to listen on (ntpd does not listen by default)
#listen on *
# sync to a single server
#server ntp.example.org
# use a random selection of NTP Pool Time Servers
# see http://support.ntp.org/bin/view/Servers/NTPPoolServers
#servers pool.ntp.org
# use a specific local timedelta sensor (radio clock, etc)
#sensor nmea0
# use all detected timedelta sensors
#sensor *
# get the time constraint from a well-known HTTPS site
#constraints from "https://www.google.com/search?q=openntpd"
# Choose servers announced from Gentoo NTP Pool
servers 0.gentoo.pool.ntp.org
servers 1.gentoo.pool.ntp.org
servers 2.gentoo.pool.ntp.org
servers 3.gentoo.pool.ntp.org
For further information see the man page:
user $man ntpd.confServer
FILE
/etc/ntpd.confOpenNTPD listening on 192.0.2.1 address while syncing with multiple servers# Addresses to listen on (ntpd does not listen by default)
listen on 192.0.2.1
# Choose servers announced from Gentoo NTP Pool
servers 0.gentoo.pool.ntp.org
servers 1.gentoo.pool.ntp.org
servers 2.gentoo.pool.ntp.org
servers 3.gentoo.pool.ntp.org
root #rc-service ntpd restartClient
FILE
/etc/ntpd.confOpenNTPD syncing with multiple servers# Choose servers announced from Gentoo NTP Pool
servers 0.gentoo.pool.ntp.org
servers 1.gentoo.pool.ntp.org
servers 2.gentoo.pool.ntp.org
servers 3.gentoo.pool.ntp.org
Alternatively sync the client to a server on the local network:
FILE
/etc/ntpd.confOpenNTPD syncing with a single server on the local network# sync to a single server on the local network
server 192.0.2.1
root #rc-service ntpd restartChecking the daemon operation
net-misc/openntpd provides the /usr/sbin/ntpctl program to display information about the running ntpd daemon:
root #ntpctl -s all4/4 peers valid, clock unsynced, clock offset is 1048.342ms
peer
wt tl st next poll offset delay jitter
185.19.184.35 0.gentoo.pool.ntp.org
1 10 2 23s 34s 41.650ms 190.744ms 227.001ms
31.14.131.188 1.gentoo.pool.ntp.org
1 10 2 2s 31s 15.834ms 132.072ms 92.419ms
212.45.144.3 2.gentoo.pool.ntp.org
1 10 1 8s 33s 42.733ms 216.937ms 212.899ms
188.213.165.209 3.gentoo.pool.ntp.org
1 10 2 19s 30s 45.672ms 228.337ms 240.018ms
The output shows how many servers the daemon is syncing with, the status of the system clock (synced/unsynced) and the clock offset. For further information see the man page:
user $man ntpctlSee also
- Ntp — is a suite of tools utilizing Network Time Protocol. Their purpose is to keep the system clock in time.
- Chrony — a versatile implementation of the Network Time Protocol (NTP).
- Network Time Protocol — is used to synchronize the system time with other devices over the network.
- System time — is used in Unix systems to keep track of time.
- Home router — how to turn an old Gentoo machine into a router for connecting a home network to the Internet.