TLS:
openssl s_client -starttls smtp -connect smtp.gmail.com:587 -crlf -ign_eof
SSL:
openssl s_client -connect smtp.gmail.com:465 -crlf -ign_eof

SMTP <- FROM SERVER:220 2.0.0 Ready to start TLS
SMTP -> TO SERVER: RSET
SMTP <- FROM SERVER:
SMTP -> ERROR: RSET failed:
SMTP -> NOTICE: EOF caught while checking if connectedThe following From address failed: test@mydomain.com Mailer Error: The following From address failed: test@mydomain.com

SSL Version OpenSSL/0.9.8o

OpenSSL support enabled
OpenSSL Library Version OpenSSL 0.9.8o 01 Jun 2010