This will configure an Asustor NAS running ADM 5 to use a letsencrypt issued certificate without exposing the NAS to the internet (by using DNS Challenge instead of using port forwarding). To accomplish this, we need to use certbot with DNS-01 challenge to Cloudflare. To perform this task, you must SSH into the NAS.
- Elevate the terminal to root
sudo su
- Setup the required directories