Openssl

connect to ssl at the command line:

https:

openssl s_client -connect server:443

smtp tls:

openssl s_client -connect server:25 -starttls smtp

more here: http://www.madboa.com/geek/openssl/

CA or not CA

Web Server Cert:

       X509v3 extensions:
           X509v3 Basic Constraints: critical
               CA:FALSE

CA Cert:

      X509v3 extensions:
          X509v3 Basic Constraints: critical
              CA:TRUE

Supported Cyphers

You are configuring your favourite app that uses openssl libs. You give it a "cyphers string". Am I allowing bad varitions?

openssl ciphers -v TLSv1.2:+TLSv1.1:+SHA384:+SHA256:+SHA1:+MD5

Will spit out a lit of the supported cypher variations.

Matching key with cert

openssl x509 -noout -modulus -in certificate.crt | openssl md5
openssl rsa -noout -modulus -in privateKey.key | openssl md5
openssl req -noout -modulus -in CSR.csr | openssl md5

Certificate Verification Tools

https://www.sslshopper.com/ssl-checker.html

https://www.ssllabs.com/ssltest/