# echo -e "ehlo eschelon.co.uk\nauth login\nbWNwQGVzY2hlbG9uLmNvLnVr\nSANITISED\nmail from: mcp@eschelon.co.uk\nrcpt to: <PRIVATEEMAIL>\ndata\nSubject: testing Auth SMTP\ntesting 123\n.\nnquit\n" | nc localhost 25
220 auth-smtp-01.streamline.net ESMTP Postfix
250-auth-smtp-01.streamline.net
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
334 VXNlcm5hbWU6
334 UGFzc3dvcmQ6
235 2.0.0 Authentication successful
250 2.1.0 Ok
553 5.7.1 <mcp@eschelon.co.uk>: Sender address rejected: not owned by user mcp@eschelon.co.uk
554 5.5.1 Error: no valid recipients
221 2.7.0 Error: I can break rules, too. Goodbye.


from /var/log/maillog:

Mar 30 13:20:29 auth-smtp-01 postfix/smtpd[21629]: connect from unknown[213.171.217.184]
Mar 30 13:20:30 auth-smtp-01 postfix/smtpd[21629]: NOQUEUE: reject: RCPT from unknown[213.171.217.184]: 553 5.7.1 <mcp@eschelon.co.uk>: Sender address rejected: not owned by user mcp@eschelon.co.uk; from=<mcp@eschelon.co.uk> to=<tomofboellan@gmail.com> proto=ESMTP helo=<eschelon.co.uk>


[root@auth-smtp-01 ~]# postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES
sample_directory = /usr/share/doc/postfix-2.3.3/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_recipient_restrictions = permit_mynetworks    permit_sasl_authenticated    reject
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = smtpd
smtpd_sender_restrictions = reject_authenticated_sender_login_mismatch
unknown_local_recipient_reject_code = 550