Creating ROOT-CA-based certificates for Synology Diskstation
The first step is to create a Certificate Signing Request (CSR) on the Synology Diskstation.

Then I’m uploading the CSR on my Virtual Machine where the Root-CA is “running” on. As Root-CA I’m using a GNU/Debian Linux with Xca (X - Certificate and Key management) installed.

After the signed certifcate is created (and transferred from the virtual machine) I am just importing it on the Synology Diskstation.

After the restart of Synologys internal web server I am verifying if the certificate is working as expected.
