kazulog@sv1:~$ echo 'Port 2222' | sudo tee -a /etc/ssh/sshd_config.d/10-hardening.conf
Port 2222
kazulog@sv1:~$ sudo sshd -t && sudo systemctl reload ssh
kazulog@sv1:~$ sudo sshd -T | grep -i '^port'
port 2222
kazulog@sv1:~$ ss -tlnp | grep -E ':22|:2222'
LISTEN 0      4096         0.0.0.0:22        0.0.0.0:*
LISTEN 0      4096            [::]:22           [::]:*          
kazulog@sv1:~$ ssh -p 2222 taro@localhost whoami
ssh: connect to host localhost port 2222: Connection refused
kazulog@sv1:~$ systemctl is-enabled ssh ssh.socket
disabled
enabled
kazulog@sv1:~$ systemctl cat ssh.socket | grep -A3 '\[Socket\]'
[Socket]
ListenStream=0.0.0.0:22
ListenStream=[::]:22
BindIPv6Only=ipv6-only