F/W設定と確認

$ sudo ufw allow from 192.99.xxx.xxx to any port 53 proto tcp comment 'for OVH monitoring'
$ sudo ufw allow from 192.99.xxx.xxx to any port 3389 proto tcp comment 'for OVH monitoring'
$ sudo ufw app list
Available applications:
  Nginx Full
  Nginx HTTP
  Nginx HTTPS
  OpenSSH
$ sudo ufw status verbose