Using the command line - OpenSSL
- Open a terminal.
- Run openssl s_client -showcerts -connect www.example.com:443 </dev/null, with your domain name.
- If successful, you’ll receive a complete output of what a browser uses to establish secure HTTP.
Using an online tool - DigiCert
- Browse to an online certificate checking service such as: https://www.digicert.com/help
- Enter your domain name and initiate the check
- Verify your setup receives a tick at the bottom of the test