Hi,

I have changed the POSTCONF setting for smtpd_reject_unlisted_recipient to "yes" as listed in the wiki...

found this in the log, which has a non-existant user on my system...

Code:
Jul  8 04:18:16 mail postfix/cleanup[12279]: 300106D58233: message-id=<4E16DA3E.109050@ms2.hinet.net>
Jul  8 04:18:16 mail postfix/qmgr[14139]: 300106D58233: from=<alybalf@ms2.hinet.net>, size=63646, nrcpt=1 (queue active)
Jul  8 04:18:16 mail zmmailboxdmgr[12956]: status requested
Jul  8 04:18:16 mail zmmailboxdmgr[12956]: status OK
Jul  8 04:18:16 mail amavis[6620]: (06620-09) ESMTP::10024 /opt/zimbra/data/amavisd/tmp/amavis-20110707T223833-06620: <alybalf@ms2.hinet.net>
 -> <binge@mydomain.com> SIZE=63646 Received: from mail.mydomain.com ([127.0.0.1]) by localhost (mail.mydomain.com [1
27.0.0.1]) (amavisd-new, port 10024) with ESMTP for <binge@mydomain.com>; Fri,  8 Jul 2011 04:18:16 -0700 (PDT)
Jul  8 04:18:16 mail amavis[6620]: (06620-09) Checking: lM0hI3YAi7ms [92.85.223.146] <alybalf@ms2.hinet.net> -> <binge@mydomain.com>
Jul  8 04:18:17 mail postfix/smtpd[12275]: disconnect from unknown[92.85.223.146]
Jul  8 04:18:18 mail postfix/smtpd[13083]: connect from localhost.localdomain[127.0.0.1]
Jul  8 04:18:18 mail postfix/smtpd[13083]: CFD346D58238: client=localhost.localdomain[127.0.0.1]
Jul  8 04:18:18 mail postfix/cleanup[12279]: CFD346D58238: message-id=<4E16DA3E.109050@ms2.hinet.net>
Jul  8 04:18:19 mail postfix/qmgr[14139]: CFD346D58238: from=<alybalf@ms2.hinet.net>, size=64526, nrcpt=1 (queue active)
Jul  8 04:18:19 mail postfix/smtpd[13083]: disconnect from localhost.localdomain[127.0.0.1]
Jul  8 04:18:19 mail amavis[6620]: (06620-09) FWD via SMTP: <alybalf@ms2.hinet.net> -> <binge@mydomain.com>,BODY=7BIT 250 2.0.0 Ok, i
d=06620-09, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as CFD346D58238
Jul  8 04:18:19 mail amavis[6620]: (06620-09) Passed SPAMMY, [92.85.223.146] [92.85.223.146] <alybalf@ms2.hinet.net> -> <binge@mydomain.com>, Message-ID: <4E16DA3E.109050@ms2.hinet.net>, mail_id: lM0hI3YAi7ms, Hits: 12.21, size: 63645, queued_as: CFD346D58238, 2481 ms
Jul  8 04:18:19 mail postfix/smtp[12957]: 300106D58233: to=<binge@mydomain.com>, orig_to=<binge@atomic.tv>, relay=127.0.0.1[127.0.0.1
]:10024, delay=67, delays=65/0.01/0/2.5, dsn=2.0.0, status=sent (250 2.0.0 Ok, id=06620-09, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued
 as CFD346D58238)
Jul  8 04:18:19 mail postfix/qmgr[14139]: 300106D58233: removed
Jul  8 04:18:19 mail postfix/error[13086]: CFD346D58238: to=<binge@mydomain.com>, relay=none, delay=0.46, delays=0.32/0.02/0/0.11, ds
n=5.0.0, status=bounced (mydomain.com)
Jul  8 04:18:19 mail postfix/cleanup[12279]: 4BA166D5827E: message-id=<20110708111819.4BA166D5827E@mail.mydomain.com>
Jul  8 04:18:19 mail postfix/bounce[13087]: CFD346D58238: sender non-delivery notification: 4BA166D5827E
Jul  8 04:18:19 mail postfix/qmgr[14139]: 4BA166D5827E: from=<>, size=3838, nrcpt=1 (queue active)
Jul  8 04:18:19 mail postfix/qmgr[14139]: CFD346D58238: removed
Jul  8 04:18:22 mail postfix/smtp[13102]: 4BA166D5827E: to=<alybalf@ms2.hinet.net>, relay=msx-smtp5.hinet.net[168.95.5.82]:25, delay=3.3, del
ays=0.11/0.01/2.2/0.95, dsn=2.0.0, status=sent (250 p68BIGEe001609 Message accepted for delivery)
Jul  8 04:18:22 mail postfix/qmgr[14139]: 4BA166D5827E: removed
when I tried to send to "binge@mydomain.com" I get the following:

Code:
Jul  8 20:40:01 mail zimbramon[5583]: 5583:info: 2011-07-08 20:40:01, QUEUE: 5 1 
Jul  8 20:40:15 mail postfix/smtpd[5909]: connect from mail-vw0-f47.google.com[209.85.212.47]
Jul  8 20:40:15 mail postfix/smtpd[5909]: NOQUEUE: reject: RCPT from mail-vw0-f47.google.com[209.85.212.47]: 550 5.1.1 <binge@mydomain.com>: Recipient address rejected: mydomain.com; from=<mygmailaccount@gmail.com> to=<binge@mydomain.com> proto=ESMTP helo=<mail-vw0-f47.google.com>
Jul  8 20:40:15 mail postfix/smtpd[5909]: disconnect from mail-vw0-f47.google.com[209.85.212.47]
can anyone explain to me:

was the e-mail from hinet.net NDR spam? And was it bounced back to the victim?

If so, how was that accomplished, versus when I attempted to send to the same non-existant user through my gmail account?

thank you