I think that I am having a problem with this also. My log file shows this:
Jun 8 01:12:23 pandora smtpd[3042]: smtp connection from UNKNOWN@localhost(127.0.0.1) MAIL FROM: vid.hedeman@zadv.com> RCPT TO: , allowed by line 22 of /etc/smtpd_check_rules
I also notice that this "user" (david.hedeman) has sent nearly 32,000 emails. Most of that was sent last Sunday when he was not in the office.
I am newbie, is this a spammer somehow using 127.0.0.1 to send? Also any suggestions on how I can fix this?
Thanks