kazulog@sv1:~$ cat /etc/os-release | head -2
PRETTY_NAME="Ubuntu 26.04 LTS"
NAME="Ubuntu"
kazulog@sv1:~$ cat /etc/chrony/conf.d/kazulog-ntp.conf
# 社内 NTP サーバー（R1）を使う
server 192.168.100.1 iburst
allow 192.168.100.0/24
kazulog@sv1:~$ ss -ulpn | grep 123
UNCONN 0      0            0.0.0.0:123       0.0.0.0:*
kazulog@sv1:~$ sudo chronyc clients
Hostname                      NTP   Drop Int IntL Last     Cmd   Drop Int  Last
===============================================================================
192.168.100.20                  6      0   1   -    52       0      0   -     -
kazulog@sv1:~$ chronyc tracking | head -3
Reference ID    : C0A86401 (192.168.100.1)
Stratum         : 4
Ref time (UTC)  : Fri Sep 11 07:36:26 2026