Am I backscattering? and non mail user accounts having mail received.

Question

10.6.4 Server fresh install on a new Mac Pro. I have configured our mail server using only Server Admin. Junk mail is set to be redirected to the junkmail account and not bounced.
FIRST ISSUE - am I backscattering? In looking at the logs I see what looks to me like attempts by our server to notify a presumably forged sender that their message was being turned down by our server. The log listing below for 1 message as an example uses the term bounced once each for the destined user (who is set NOT to receive mail in WGM) and our postmaster account.
I am seeing lists of delayed items in the mail queue in Server Admin > Mail > Maintenance > Mail Queue. All of those messages are going from the Mailer-daemon to the presumably forged FROM: address of items delivered to our junkmail account.
SECOND ISSUE : The requested user in this example does not exist as an email recipient on the server. Shouldn't the message be refused outright? These messages are being accepted by the server and Server Admin > Mail > Maintenance > Accounts keeps showing mail accounts for the user here and another user that are the server is not accepting mail for. If I delete the account in Server Admin window above, they return again within a day or so. Ideas?
Thanks for looking at this.
-Erich
Log and postconf -n below.
Sep 27 09:00:04 Web postfix/cleanup[11390]: B33908BDE8: message-id=<[email protected]>
Sep 27 09:00:04 Web postfix/bounce[11401]: 8EB168BDDB: sender non-delivery notification: B33908BDE8
Sep 27 09:00:04 Web postfix/qmgr[88689]: B33908BDE8: from=, size=9475, nrcpt=1 (queue active)
Sep 27 09:00:04 Web postfix/smtp[11374]: B33908BDE8: enabling PIX workarounds: disable_esmtp delay_dotcrlf for rza11.usagems.info[98.126.94.11]:25
Sep 27 09:00:06 Web postfix/smtp[11374]: B33908BDE8: to=<[email protected]>, relay=rza11.usagems.info[98.126.94.11]:25, delay=1.3, delays=0/0/0.31/0.98, dsn=2.6.0, status=sent (250 2.6.0 message received)
Sep 27 09:00:06 Web postfix/qmgr[88689]: B33908BDE8: removed
Sep 27 09:00:03 Web postfix/smtpd[11382]: 8EB168BDDB: client=unknown[98.126.94.11]
Sep 27 09:00:04 Web postfix/cleanup[11390]: 8EB168BDDB: message-id=<[email protected]za 11.usagems.info>
Sep 27 09:00:04 Web postfix/qmgr[88689]: 8EB168BDDB: from=<[email protected]>, size=7452, nrcpt=2 (queue active)
Sep 27 09:00:04 Web postfix/smtp[11396]: 8EB168BDDB: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=1.3, delays=0.73/0.01/0/0.53, dsn=5.7.0, status=bounced (host 127.0.0.1[127.0.0.1] said: 554 5.7.0 Reject, id=78657-16 - SPAM (in reply to end of DATA command))
Sep 27 09:00:04 Web postfix/smtp[11396]: 8EB168BDDB: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=1.3, delays=0.73/0.01/0/0.53, dsn=5.7.0, status=bounced (host 127.0.0.1[127.0.0.1] said: 554 5.7.0 Reject, id=78657-16 - SPAM (in reply to end of DATA command))
Sep 27 09:00:04 Web postfix/bounce[11401]: 8EB168BDDB: sender non-delivery notification: B33908BDE8
Sep 27 09:00:04 Web postfix/qmgr[88689]: 8EB168BDDB: removed
always_bcc = [email protected]
biff = no
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
debugpeerlevel = 2
enableserveroptions = yes
header_checks = pcre:/etc/postfix/customheaderchecks
html_directory = /usr/share/doc/postfix/html
inet_interfaces = all
localrecipientmaps = proxy:unix:passwd.byname $alias_maps
mail_owner = _postfix
mailboxsizelimit = 0
mailbox_transport = dovecot
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
mapsrbldomains =
messagesizelimit = 31457280
mydestination = $myhostname, localhost.$mydomain, localhost, web.wetzelandson.com, wetzelandson.com, mail.wetzelandson.com, www.wetzelandson.com, $mydomain
mydomain = wetzelandson.com
mydomain_fallback = localhost
myhostname = mail.wetzelandson.com
mynetworks = 127.0.0.0/8,192.168.0.0/16,192.168.1.4,192.168.1.2,192.168.1.3
newaliases_path = /usr/bin/newaliases
queue_directory = /private/var/spool/postfix
readme_directory = /usr/share/doc/postfix
recipient_delimiter = +
relayhost =
sample_directory = /usr/share/doc/postfix/examples
sendmail_path = /usr/sbin/sendmail
setgid_group = _postdrop
smtpdclientrestrictions = permit_mynetworks permitsaslauthenticated rejectrblclient zen.spamhaus.org permit
smtpdenforcetls = no
smtpdhelorequired = yes
smtpdhelorestrictions = rejectinvalid_helohostname rejectnon_fqdn_helohostname
smtpdpw_server_securityoptions = cram-md5,gssapi
smtpdrecipientrestrictions = permitsaslauthenticated permit_mynetworks rejectunauthdestination checkpolicyservice unix:private/policy permit
smtpdsasl_authenable = yes
smtpdtlsCAfile = /etc/certificates/mail.wetzelandson.com.305A920E5E97BCE93548C2DE35BC3332F3EB440 F.chain.pem
smtpdtls_certfile = /etc/certificates/mail.wetzelandson.com.305A920E5E97BCE93548C2DE35BC3332F3EB440 F.cert.pem
smtpdtls_excludeciphers = SSLv2, aNULL, ADH, eNULL
smtpdtls_keyfile = /etc/certificates/mail.wetzelandson.com.305A920E5E97BCE93548C2DE35BC3332F3EB440 F.key.pem
smtpduse_pwserver = yes
smtpdusetls = yes
tlsrandomsource = dev:/dev/urandom
unknownlocal_recipient_rejectcode = 550
virtualaliasmaps = $virtual_maps

Answer 1

Any ideas? I have not been able to find anything persuasive for either of these questions.