NTPD

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NTPD (Network Time Protokol Daemon)

Description

The NTPD program is an operating-system daemon that sets and maintains a computer system's system time in synchronization with Internet-standard time servers. It is a complete implementation of the Network Time Protocol (NTP) version 4, but retains compatibility with versions 1, 2, and 3 as defined by RFC 1059, RFC 1119, and RFC 1305, respectively. ntpd performs most computations in 64-bit floating point arithmetic and uses 64-bit fixed point operations only when necessary to preserve the ultimate precision, about 232 picoseconds. While ordinary workstations and networks cannot achieve the ultimate precision as of 2015, future processors and networks may require it.

NTPD Installation

To install NTPD package simply use the following commands:

1. Update List of Available Packages

root@iplog:~# opkg update

Example of update process:

Downloading http://www.iplog.eu/opkg/base/Packages.gz.
Updated source 'base'.
Downloading http://www.iplog.eu/opkg/firmware/Packages.gz.
Updated source 'firmware'.

2. Upgrade Installed Packages

root@iplog:~# opkg upgrade

3. Install NTPD Package

root@iplog:~# opkg install ntpd

Example of package installing:

Installing ntpd (4.2.8p9-9671.212083251) on root.
Downloading http://www.iplog.eu/opkg/base/ntpd_4.2.8p9-9671.212083251_all.ipk.
Configuring ntpd.

Configuration Examples

This section provides several examples of the /etc/ntpd.conf configuration file.

1. Standalone NTP server

The following configuration has the following features:

- Local NTP server with specified stratum 10

- No synchronization to internet NTP servers

Editing configuration file command:

root@iplog:~# vi /etc/ntpd.conf

File content:

restrict default

# create a local NTP server
server 127.127.1.0
fudge 127.127.1.0 stratum 10

driftfile /tmp/ntp.drift

2. With Connetion to Remote NTP Servers

Example shows the optimal configuration for the Czech Republic.

This configuration has the following features:

- Local NTP server with specified stratum 10

- Synchronization to two internet NTP servers

Editing configuration file command:

root@iplog:~# vi /etc/ntpd.conf

File content:

restrict default
#restrict source
#interface listen wildcard

server tik.cesnet.cz
server tak.cesnet.cz

server 127.127.1.0
fudge 127.127.1.0 stratum 10 refid ILOG

driftfile /tmp/ntp.drift
#end-of-file