I found a simple example for SMTP/ESMTP:
SMTP
----
220 mail.example.com SMTP service ready
HELO client....
250 mail.example.com - Hello, nice to meet you!
MAIL FROM:
250 ok
...
ESMTP Auth login
----------------
(If the server wouldn't understand ESMTP's he would answer with an
error to the EHLO. Then a fallback to HELO has to be done.)
220 mail.example.com SMTP service ready
EHLO client....
250-mail.example.com - Hello, nice to meet you!
250-AUTH LOGIN CRAM-MD5 PLAIN
250-AUTH=LOGIN CRAM-MD5 PLAIN
250-PIPELINING
250 SIZE 31457280
AUTH LOGIN # client wishes to authenticate
334 VXNlcm5hbWU6 # server asks (base64): "Username:"
TWVpbiBVc2VybmFtZSA6LSk= # client sends username (base64)
334 UGFzc3dvcmQ6 # server asks (base64): "Password:"
TWVpbktlbm53b3J0 # client sends username (base64)
235 ok, go ahead
MAIL FROM:
250 ok
...
Christian