openssl verify

Make a folder to contain your public certificates:

#mkdir certs
#cd certs

Get public cert for the server you want to check:
#openssl s_client -showcerts -connect server:port

Copy from the "-----BEGIN CERTIFICATE-----" to the "-----END CERTIFICATE-----" , and save it in a file ending in .pem

Get issuer (CA) root certificate ("Certification Authority Root Certificate")
should be provided by your issuer or if you are your own CA you should know how to get this. Place it in the same directory as the certificate of your server (the one you are testing).

 Rehash the certificates. This is basically creating a link files to your .pem files. Names are based on the certificate content so openssl command will be able to operate on the files.

#for file in *.pem; do ln -s $file `openssl x509 -hash -noout -in $file`.0; done

Verify the certificate:

#openssl s_client -CApath . -connect server:port

Output should be similar to:
..
..
..
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : DES-CBC3-SHA
    Session-ID: 53563D55F85CD643713643B7163A8C25113B114703C975DEA1C57D659FFBF96E
    Session-ID-ctx:
    Master-Key: 7288C083E0723BC61C4C21DC91908E34BD5C65695064E4E114FF4ED763ECA1D489794B9911E69021B8A8083A9CAB18EE
    Key-Arg   : None
    Krb5 Principal: None
    PSK identity: None
    PSK identity hint: None
    Start Time: 1398160725
    Timeout   : 300 (sec)
    Verify return code: 0 (ok)
---
..
..

If you see Verify return code: 0 (ok) you are good!