Tim,

  I went to register for the bugzilla and found that the confirmation request
from 74.84.118.181 was rejected by postfix because 74.84.118.181 does not
provide a proper reverse lookup causing:

smtpd_client_restrictions = reject_rbl_client sbl.spamhaus.org,
reject_unknown_client

  It is 'reject_unknown_client' causing the rejection. From:
http://www.postfix.org/postconf.5.html the rejection is caused when:

1) the client IP address->name mapping fails, 2) the name->address mapping
fails, or 3) the name->address mapping does not match the client IP address.

  I'm no postfix expert, but to let the confirmation through, I just removed
'reject_unknown_client'. If there have been people who don't get the
confirmation emails, this may one reason why :)

  The actual postfix rejection was:

Feb 28 16:22:21 nirvana postfix/smtpd[6858]: warning: 74.84.118.181: address not
listed for hostname pearsoncomputing.net
Feb 28 16:22:21 nirvana postfix/smtpd[6858]: connect from unknown[74.84.118.181]
Feb 28 16:22:22 nirvana postfix/smtpd[6858]: NOQUEUE: reject: RCPT from
unknown[74.84.118.181]: 450 4.7.1 Client host rejected: cannot find your
hostname, [74.84.118.181]; from=<bugs@...> to=<snip>
proto=ESMTP helo=<vali.starlink.edu>
Feb 28 16:22:22 nirvana postfix/smtpd[6858]: disconnect from unknown[74.84.118.181]

  Somebody smart with postfix and bind can probably tell you what the exact
issue is. Just looking, I see a helo from vali.starlink.edu and the "warning:
74.84.118.181: address not listed for hostname pearsoncomputing.net"


-- 
David C. Rankin, J.D.,P.E.