[root@echo7 ~]# cat /var/log/maillog

Sep 20 14:54:01 echo7 sendmail[1595]: o8KIs1jG001595: from=root, size=2036, class=0, nrcpts=1, msgid=<201009201854.o8KIs1jG001595@echo7.ntertech.com>, relay=root@localhost
Sep 20 14:54:01 echo7 sendmail[1599]: o8KIs1pS001599: from=<root@echo7.ntertech.com>, size=2284, class=0, nrcpts=1, msgid=<201009201854.o8KIs1jG001595@echo7.ntertech.com>, proto=ESMTP, daemon=MTA, relay=echo7.ntertech.com [127.0.0.1]
Sep 20 14:54:01 echo7 sendmail[1595]: o8KIs1jG001595: to=ben@nospam.com, ctladdr=root (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=32036, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (o8KIs1pS001599 Message accepted for delivery)
Sep 20 14:54:02 echo7 postfix/smtpd[1578]: warning: 208.100.63.215: address not listed for hostname echo7.ntertech.com
Sep 20 14:54:02 echo7 postfix/smtpd[1578]: connect from unknown[208.100.63.215]
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs1pS001599: SYSERR(root): ntertech.com. config error: mail loops back to me (MX problem?)
Sep 20 14:54:02 echo7 postfix/smtpd[1578]: disconnect from unknown[208.100.63.215]
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs1pS001599: to=<ben@nospam.com>, ctladdr=<root@echo7.ntertech.com> (0/0), delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122284, relay=ntertech.com. [208.100.63.215], dsn=5.3.5, stat=Local configuration error
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs1pS001599: o8KIs2pS001601: DSN: Local configuration error
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs2pS001601: to=ben@nospam.com, delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=33514, relay=ntertech.com., dsn=5.3.5, stat=Local configuration error
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs2pS001601: o8KIs2pT001601: return to sender: Local configuration error
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs2pT001601: to=ben@nospam.com, delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=34538, relay=ntertech.com., dsn=5.3.5, stat=Local configuration error
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs2pS001601: Losing ./qfo8KIs2pS001601: savemail panic
Sep 20 14:54:02 echo7 sendmail[1601]: o8KIs2pS001601: SYSERR(root): savemail: cannot save rejected email anywhere