$./a.out smtp.gmail.com 25
220 mx.google.com ESMTP 9sm2923369yxf.23

250 mx.google.com at your service

220 2.0.0 Ready to start TLS

after handshake
Common Name: smtp.gmail.com
after get cert dn
-----BEGIN SSL SESSION PARAMETERS-----
d4f65cac7d180d5b17d3f6334cf60bcaee84cea782dc39be68 e9224d06ec9b86
-----END SSL SESSION PARAMETERS-----
CIPHER is RC4-MD5

EHLO
250-mx.google.com at your service, [61.11.23.15]
250-SIZE 35651584
250-8BITMIME
250-AUTH LOGIN PLAIN
250-ENHANCEDSTATUSCODES
250 PIPELINING
MAIL FROM:<root@stripe>
502 5.5.1 Unrecognized command. 9sm2923369yxf.23


Above program just connect to smtp.gmail.com@25 and send
1) HELO
2) STARTTLS
..
After succ handshake we need to send EHELO again. I have sent EHELO but after that whne I semt MAIL FROM it give me unrecognized command why?