- SSH to your nas drive
- Upload your pem certificate
- sudo su –
- Backup first; cp /etc/ssl/certs/ca-certificates.crt /var/tmp/ca-certificates.crt.bak
- cat yourfile.pem >> /etc/ssl/certs/ca-certificates.crt
Note: This is not officially supported by synology. A future Update could restore the list of root-ca-certs to default and then you’d have to import the cert again.