I just got an e-mail that my certificate is about to expire in 20 days, but there was no information how to renew my certificate. I found settings deep in my Synology NAS and clicked Renew certificate. There was no indication that there was success or failure to renew the certificate. How do I know if the renewal has worked? Which procedure is normally used when renewing the certificate? Can I make it happen automatically?
Where do you use your certificate for? A website? You can check the certificate in your browser. It depends on the browser how though, use Google to find out.
It is for remote backup purpose so there is no web page to go to to get certificate info from a f a i k. I have tried to surf to the address, but there is no response.
For every TLS enabled service you should be able to connect to it with the
openssl s_client command. You'd need to find out which port is used for that backup service and connect to it using:
openssl s_client -connect $hostname_or_ip_address:$portnumber
This would show you the PEM encoded certificate, which isn't very useful, but luckily you can pipe that directlly to the
openssl x509 module:
openssl s_client -connect $hostname_or_ip_address:$portnumber | openssl x509 -noout -text
This should show you the certificate currently in use with the service you connected to.