[Mimedefang] Milter failure processing Read and Delivery Receipts

[Jim Crippen]

For the past couple days we have been experiencing a very high volume of
failures with Mimedefang and Spamassassin.  Over 90% of the messages are
either Read Receipts or Delivered Receipts.  Mimedefang and sendmail are
posting the "reject=451 4.7.1 Please try again later".  Below is a full
exerpt from the mail log on one of these failures.

Mar  4 08:36:22 smtp2 sendmail[17411]: i24EaLUE017411: from=<>, size=2761,
class=0, nrcpts=1, msgid=<200403021600.i22G0613011695 at gateway1c.dhl.com>,
bodytype=8BITMIME, proto=ESMTP, daemon=MTA, relay=ssf163a.dhl.com
[199.41.197.163]
Mar  4 08:36:32 smtp2 sendmail[17411]: i24EaLUE017411: Milter (mimedefang):
timeout before data read
Mar  4 08:36:32 smtp2 sendmail[17411]: i24EaLUE017411: Milter (mimedefang):
to error state
Mar  4 08:36:32 smtp2 sendmail[17411]: i24EaLUE017411: Milter: data,
reject=451 4.7.1 Please try again later
Mar  4 08:36:32 smtp2 sendmail[17411]: i24EaLUE017411:
to=<vwilson at eliteint.com>, delay=00:00:11, pri=32761, stat=Please try again
later
Mar  4 08:36:33 smtp2 mimedefang.pl[14222]:
MDLOG,i24EaLUE017411,spam,-3.25,199.41.197.163,<>,<vwilson at eliteint.com>,Ret
urn receipt
Mar  4 08:36:33 smtp2 mimedefang[17412]: i24EaLUE017411: smfi_addrcpt
returned MI_FAILURE
Mar  4 08:36:33 smtp2 mimedefang[17412]: i24EaLUE017411: smfi_chgheader
returned MI_FAILURE
Mar  4 08:36:33 smtp2 mimedefang[17412]: i24EaLUE017411: smfi_addheader
returned MI_FAILURE

The only change we have made is added a filter_sender to bypass known
senders.  We have disabled this filter but are still experiencing the
errors.

Any help or recommendations are greatly appreciated.

Thanks.

Jim Crippen
Sr LAN Administrator
Elite Transportation
jcrippen at elitehou.com
phone: 281-775-2100