S: [wait for open connection] C: [open connection to server] S: 220 mail.example.com ESMTP service ready C: EHLO example.org S: 250-mail.example.com S: 250-SMTPUTF8 S: 250-LIMITS RCPTMAX=20 MAILMAX=5 S: 250-SIZE 100000000 S: 250-8BITMIME S: 250-ENHANCEDSTATUSCODES S: 250-PIPELINING S: 250-CHUNKING S: 250 STARTTLS