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Mikaela Suomalainen 38ef6e7314
chrony/sources/nts: add nts.netnod.se 
They appear to be the only bigger party hosting NTS in addition to
Cloudflare and being in neighbouring country isn't too bad

Via https://gist.github.com/jauderho/2ad0d441760fc5ed69d8d4e2d6b35f8d
which encouraged me to look into them a bit more. Additionally having
read chrony or chrony.conf manual on default behaviour implying NTS
servers are "require trust" and when mixing them with NTP servers, NTP
servers never get selected unless they agree with NTS servers.
2021-09-26 21:28:06 +03:00
..
conf.d chrony/conf.d: add cmd.conf 2021-08-07 23:56:38 +03:00
sources.d chrony/sources/nts: add nts.netnod.se 2021-09-26 21:28:06 +03:00
chrony.conf chrony: cut chrony.d/ into conf.d/ and sources.d/ 2021-01-29 12:56:38 +02:00
README.md etc/chrony: break chrony.conf into README.md & chrony.d/ 2020-11-01 11:23:59 +02:00

README.md

Chrony config files

For some reason Debian package for Chrony doesn’t include other config files so that has to be done by hand like

confdir /etc/chrony/chrony.d

Windows

choco install nettime

Other random notes

On pools, the default maxsources is 4 and pools would be resolved until there would be 4 names while the documentation for Telia and Snopyta says they have only 3. Cloudflare again resolves to two per IP version, so I assume that means 2.

Commands of interest:

Chrony itself

Note: -N uses names specified in config instead of reverse name lookupping then.

  • chrony -N activity - what sources are doing
  • chrony -N authdata - can show that server uses NTS
  • chrony -N ntpdata - a lot of data on the servers
  • chronyc offline - offline mode
  • chronyc online - reconnects servers
  • chrony -N sources - used timeservers and their statuses
  • chrony -N tracking - local status (stratum and own clock etc.)

nmap

Checking that something is an NTP server? Needs root:

nmap -sU -p 123 --script=ntp-info 192.168.0.1

Checking that something has NTS?

nmap -p 4460 -Pn ntp.example.net

Firewall configuration

In case local clients or peers are wanted,

ufw allow from 192.168.0.0/16 to any port 123 proto udp
ufw allow from fe80::/10 to any port 123 proto udp

A bit wide 192.168.x.x, but so is conf.d/local-servers,conf and fe80://10 isn’t ULA either.