kazulog@sv1:~$ cat /etc/os-release | head -2
PRETTY_NAME="Ubuntu 26.04 LTS"
NAME="Ubuntu"
kazulog@sv1:~$ ls -l /etc/inetd.d/
total 4
-rw-r--r-- 1 root root 90 Sep 12 09:47 echo
kazulog@sv1:~$ cat /etc/inetd.d/echo
# echo サービス（inetd の内蔵サービス）
echo	stream	tcp	nowait	root	internal
kazulog@sv1:~$ sudo systemctl restart inetutils-inetd
kazulog@sv1:~$ sudo ss -tlnp 'sport = :7'
State              Recv-Q             Send-Q                          Local Address:Port                           Peer Address:Port             Process
LISTEN             0                  10                                    0.0.0.0:7                                   0.0.0.0:*                 users:(("inetutils-inetd",pid=3692,fd=6))