OpenSSL is used most commonly to create various files required during the process of creating an SSL certificate. However, it can also be used to verify the validity of an existing SSL certificate.
Use the below command to test the validity of an SSL certificate.
Note: the -CApath option specifies the location of your locally installed certificates and certificate chains. Omit this option to see how the SSL reacts when no associated certificates or certificate chains are available.
openssl s_client -CApath /etc/ssl/certs/ -connect address.com:443