From b1cb71c71935ad6b0a7d9effe8f4dc4467de2175 Mon Sep 17 00:00:00 2001 From: rebortg Date: Mon, 30 Nov 2020 21:15:16 +0100 Subject: arrange: system configration --- docs/configuration/system/ntp.rst | 56 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 docs/configuration/system/ntp.rst (limited to 'docs/configuration/system/ntp.rst') diff --git a/docs/configuration/system/ntp.rst b/docs/configuration/system/ntp.rst new file mode 100644 index 00000000..5fd1837f --- /dev/null +++ b/docs/configuration/system/ntp.rst @@ -0,0 +1,56 @@ +.. _ntp: + +### +NTP +### + +:abbr:`NTP (Network Time Protocol`) is a networking protocol for clock +synchronization between computer systems over packet-switched, variable-latency +data networks. In operation since before 1985, NTP is one of the oldest Internet +protocols in current use. + +NTP is intended to synchronize all participating computers to within a few +milliseconds of :abbr:`UTC (Coordinated Universal Time)`. It uses the +intersection algorithm, a modified version of Marzullo's algorithm, to select +accurate time servers and is designed to mitigate the effects of variable +network latency. NTP can usually maintain time to within tens of milliseconds +over the public Internet, and can achieve better than one millisecond accuracy +in local area networks under ideal conditions. Asymmetric routes and network +congestion can cause errors of 100 ms or more. + +The protocol is usually described in terms of a client-server model, but can as +easily be used in peer-to-peer relationships where both peers consider the other +to be a potential time source. Implementations send and receive timestamps using +:abbr:`UDP (User Datagram Protocol)` on port number 123. + +NTP supplies a warning of any impending leap second adjustment, but no +information about local time zones or daylight saving time is transmitted. + +The current protocol is version 4 (NTPv4), which is a proposed standard as +documented in :rfc:`5905`. It is backward compatible with version 3, specified +in :rfc:`1305`. + +Configuration +============= + +.. cfgcmd:: set system ntp server
+ + Configure one or more servers for synchronisation. Server name can be either + an IP address or :abbr:`FQDN (Fully Qualified Domain Name)`. + + There are 3 default NTP server set. You are able to change them. + + * 0.pool.ntp.org + * 1.pool.ntp.org + * 2.pool.ntp.org + +.. cfgcmd:: set system ntp listen-address
+ + Setup VyOS as an NTP responder, you must specify the `
` and + optionally the permitted clients. Multiple listen addresses can be + configured. + +.. cfgcmd:: set system ntp allow-clients address
+ + List of networks or client addresses permitted to contact this NTP server. + Multiple networks can be configured. -- cgit v1.2.3