Aborted SMTP Transaction Scenario

         R: 220 MIT-Multics.ARPA Simple Mail Transfer Service Ready
         S: HELO ISI-VAXA.ARPA
         R: 250 MIT-Multics.ARPA

         S: MAIL FROM:<Smith@ISI-VAXA.ARPA>
         R: 250 OK

         S: RCPT TO:<Jones@MIT-Multics.ARPA>
         R: 250 OK

         S: RCPT TO:<Green@MIT-Multics.ARPA>
         R: 550 No such user here

         S: RSET
         R: 250 OK

         S: QUIT
         R: 221 MIT-Multics.ARPA Service closing transmission channel

                               Scenario 2