echo "This is my mail." | mailx -v -s "This is my title" -S from="source@mysourcedomain.com" destination@mydomain.com
LOG: MAIN
  cwd=/home/senderuser 5 args: /usr/sbin/sendmail -i -v -- destination@mydomain.com
LOG: MAIN
  <= senderuser@mysourcedomain.com U=senderuser P=local S=546 id=59ce55e3.qTFw309pim+8bVsf%source@mysourcedomain.com T="This is my title"
 LOG: MAIN
  cwd=/var/spool/exim 4 args: /usr/sbin/exim -v -Mc 1dxw6F-004MHI-IE
delivering 1dxw6F-004MHI-IE
Transport port=25 replaced by host-specific port=25
Connecting to smtp.mailchannels.net [35.164.56.36]:25 ... connected
  SMTP<< 220 relay.mailchannels.net ESMTP Postfix (Ubuntu)
  SMTP>> EHLO mysourcedomain.com
  SMTP<< 250-relay.mailchannels.net
         250-SIZE 104857600
         250-AUTH PLAIN LOGIN
         250-ENHANCEDSTATUSCODES
         250-SMTPUTF8
         250 STARTTLS
  SMTP>> STARTTLS
  SMTP<< 220 2.0.0 Start TLS
  SMTP>> EHLO mysourcedomain.com
  SMTP<< 250-relay.mailchannels.net
         250-SIZE 104857600
         250-AUTH PLAIN LOGIN
         250-ENHANCEDSTATUSCODES
         250 SMTPUTF8
  SMTP>> AUTH LOGIN
  SMTP<< 334 VXNlcm5hbWU6
  SMTP>> ************
  SMTP<< 334 UGFzc3dvcmQ6
  SMTP>> ********************************
  SMTP<< 235 2.7.0 Authentication successful
  SMTP>> MAIL FROM:<senderuser@mysourcedomain.com> SIZE=1584 AUTH=senderuser@mysourcedomain.com
  SMTP<< 250 2.1.0 Ok
  SMTP>> RCPT TO:<destination@mydomain.com>
  SMTP<< 250 2.1.5 Ok
  SMTP>> DATA
  SMTP<< 354 End data with <CR><LF>.<CR><LF>
  SMTP>> writing message and terminating "."
  SMTP<< 250 2.0.0 Ok: queued as 7B1E07C8A78
  SMTP>> QUIT
  SMTP(close)>>
LOG: MAIN
  => destination@mydomain.com R=send_via_mailchannels T=mailchannels_smtp H=smtp.mailchannels.net [35.164.56.36] X=TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256 CV=yes A=mailchannels_login C="250 2.0.0 Ok: queued as 7B1E07C8A78"
LOG: MAIN
  Completed

echo "This is my mail." | mailx -v -s "This is my title" -a temp.sql -S from="source@mysourcedomain.com" destination@mydomain.com
LOG: MAIN
  cwd=/home/senderuser 5 args: /usr/sbin/sendmail -i -v -- destination@mydomain.com
LOG: MAIN
  <= senderuser@mysourcedomain.com U=senderuser P=local S=25970046 id=59ce54f8.wAqB0smywZHcIgoC%source@mysourcedomain.com T="This is my title"
LOG: MAIN
  cwd=/var/spool/exim 4 args: /usr/sbin/exim -v -Mc 1dxw2U-004HfI-J3
delivering 1dxw2U-004HfI-J3
Transport port=25 replaced by host-specific port=25
Connecting to smtp.mailchannels.net [52.25.7.42]:25 ... connected
  SMTP<< 220 relay.mailchannels.net ESMTP Postfix (Ubuntu)
  SMTP>> EHLO mysourcedomain.com
  SMTP<< 250-relay.mailchannels.net
         250-SIZE 104857600
         250-AUTH PLAIN LOGIN
         250-AUTH=PLAIN LOGIN
         250-ENHANCEDSTATUSCODES
         250-SMTPUTF8
         250 STARTTLS
  SMTP>> STARTTLS
  SMTP<< 220 2.0.0 Start TLS
  SMTP>> EHLO mysourcedomain.com
  SMTP<< 250-relay.mailchannels.net
         250-SIZE 104857600
         250-AUTH PLAIN LOGIN
         250-AUTH=PLAIN LOGIN
         250-ENHANCEDSTATUSCODES
         250 SMTPUTF8
  SMTP>> AUTH LOGIN
  SMTP<< 334 VXNlcm5hbWU6
  SMTP>> ************
  SMTP<< 334 UGFzc3dvcmQ6
  SMTP>> ********************************
  SMTP<< 235 2.7.0 Authentication successful
  SMTP>> MAIL FROM:<senderuser@mysourcedomain.com> SIZE=26328372 AUTH=senderuser@mysourcedomain.com
  SMTP<< 250 2.1.0 Ok
  SMTP>> RCPT TO:<destination@mydomain.com>
  SMTP<< 250 2.1.5 Ok
  SMTP>> DATA
  SMTP<< 354 End data with <CR><LF>.<CR><LF>
  SMTP>> writing message and terminating "."
  SMTP<< 250 2.0.0 Ok: queued as A6BD720897C
  SMTP>> QUIT
  SMTP(close)>>
LOG: MAIN
  => destination@mydomain.com R=send_via_mailchannels T=mailchannels_smtp H=smtp.mailchannels.net [52.25.7.42] X=TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256 CV=yes A=mailchannels_login C="250 2.0.0 Ok: queued as A6BD720897C"
LOG: MAIN
  Completed