S: 220 mail.example.net ESMTP
 C: EHLO mail.example.org
 S: 250-mail.example.net Hello example.org [192.0.2.1]
 S: 250-SIZE 52428800
 S: 250-8BITMIME
 S: 250-PIPELINING
 S: 250-REQUIRETLS
 S: 250 HELP
 C: MAIL FROM:<roger@example.org> REQUIRETLS
 S: 250 OK
 C: RCPT TO:<editor@example.net>
 S: 250 Accepted
 C: DATA
 S: 354 Enter message, ending with "." on a line by itself