SMTP # telnet smtp.example.com 25 HELO mymachine MAIL FROM: <from@example.com> RCPT TO: <to@example.com> DATA From: from@example.com To: to@example.com Subject: TEST mail body is here. . QUIT ||< -SMTP Auth >|| 220 smtp.example.com ESMTP EHLO [10.0.7.1] 250-smtp.example.co</to@example.com></from@example.com>…