[exim] MIME problem in Exim 4.50

I am testing out a new installation of Exim 4.50. I currently use Exim 4.30,
and have changed the settings in the configuration file to use the inbuilt
MIME decoding rather than the deprecated demime option.

The problem I'm now having is that with most attachments I am getting a MIME
error. The $mime_anomaly_text contains "Broken BASE64 encoding detected".
I've tried it with varous zip and doc files and and 3 different mail
clients. However, some files work perfectly every time.

Is there any way to diagnose the problem?


This is the output from one instance running Exim with -d+acl:

6768 >>Headers after rewriting and local additions:
  6768 F From: Nigel Wade <nmw@???>
  6768 T To: nmw@???
  6768   Subject: test
  6768   Date: Thu, 7 Jul 2005 17:28:09 +0100
  6768   User-Agent: KMail/1.6.2
  6768   MIME-Version: 1.0
  6768   Content-Disposition: inline
  6768   Content-Type: Multipart/Mixed;
  6768   boundary="Boundary-00=_ZgVzCy02G9y9/3m"
  6768 I Message-Id: <200507071728.09373.nmw@???>
  6768
  6768 Data file written for message 1DqZFA-0001lA-2Q
  6768 >>Generated Received: header line
  6768 P Received: from [143.210.44.106] (helo=nmw-office.ion.le.ac.uk)
  6768   by mail.ion.le.ac.uk with esmtp (Exim 4.50)
  6768   id 1DqZFA-0001lA-2Q
  6768   for nmw@???; Thu, 07 Jul 2005 17:28:56 +0100
  6768 Found Content-Type: header - executing acl_smtp_mime.
  6768 Found content-disposition: MIME header, value is 'inline'
  6768 Found content-type: MIME header, value is 'multipart/mixed'
  6768 Found boundary= MIME parameter in content-type: header, value is 
'Boundary-00=_ZgVzCy02G9y9/3m'
  6768 using ACL "acl_check_mime"
  6768 processing "deny"
  6768 check condition = ${if match {${lc:$mime_filename}} 
{\N(\.exe|\.scr|\.vbs|\.pif|\.bat|\.scr|\.lnk|
\.com)$\N} {1}{0}}
  6768                 = 0
  6768 deny: condition test failed
  6768 processing "deny"
  6768 check decode = default
  6768 check condition = ${if > {$mime_anomaly_level}{1} {true}{false}}
  6768                 = false
  6768 deny: condition test failed
  6768 processing "accept"
  6768 accept: condition test succeeded
  6768 Entering multipart recursion, boundary 'Boundary-00=_ZgVzCy02G9y9/3m'
  6768 Next part with boundary Boundary-00=_ZgVzCy02G9y9/3m
  6768 Found content-type: MIME header, value is 'text/plain'
  6768 Found charset= MIME parameter in content-type: header, value is 
'us-ascii'
  6768 Found content-transfer-encoding: MIME header, value is '7bit'
  6768 Found content-disposition: MIME header, value is 'inline'
  6768 using ACL "acl_check_mime"
  6768 processing "deny"
  6768 check condition = ${if match {${lc:$mime_filename}} 
{\N(\.exe|\.scr|\.vbs|\.pif|\.bat|\.scr|\.lnk|
\.com)$\N} {1}{0}}
  6768                 = 0
  6768 deny: condition test failed
  6768 processing "deny"
  6768 check decode = default
  6768 check condition = ${if > {$mime_anomaly_level}{1} {true}{false}}
  6768                 = false
  6768 deny: condition test failed
  6768 processing "accept"
  6768 accept: condition test succeeded
  6768 Next part with boundary Boundary-00=_ZgVzCy02G9y9/3m
  6768 Found content-type: MIME header, value is 'application/x-zip'
  6768 Found name= MIME parameter in content-type: header, value is 'test.zip'
  6768 Found content-transfer-encoding: MIME header, value is 'base64'
  6768 Found content-disposition: MIME header, value is 'attachment'
  6768 Found filename= MIME parameter in content-disposition: header, value 
is 'test.zip'
  6768 using ACL "acl_check_mime"
  6768 processing "deny"
  6768 check condition = ${if match {${lc:$mime_filename}} 
{\N(\.exe|\.scr|\.vbs|\.pif|\.bat|\.scr|\.lnk|
\.com)$\N} {1}{0}}
  6768                 = 0
  6768 deny: condition test failed
  6768 processing "deny"
  6768 check decode = default
  6768 check condition = ${if > {$mime_anomaly_level}{1} {true}{false}}
  6768                 = true
  6768 deny: condition test succeeded
  6768 unspool_mbox(): unlinking 
'/var/spool/exim/scan/1DqZFA-0001lA-2Q/1DqZFA-0001lA-2Q-00002'
  6768 unspool_mbox(): unlinking 
'/var/spool/exim/scan/1DqZFA-0001lA-2Q/1DqZFA-0001lA-2Q-00000'
  6768 unspool_mbox(): unlinking 
'/var/spool/exim/scan/1DqZFA-0001lA-2Q/1DqZFA-0001lA-2Q-00001'
  6768 unspool_mbox(): unlinking 
'/var/spool/exim/scan/1DqZFA-0001lA-2Q/1DqZFA-0001lA-2Q.eml'
  6768 SMTP>> 550-Message rejected. The message contains a MIME error 
(Broken BASE64 encoding
  6768 SMTP>> 550 detected)
  6768 LOG: MAIN REJECT
  6768   H=(nmw-office.ion.le.ac.uk) [143.210.44.106] F=<nmw@???> 
rejected during MIME ACL check                                       s: MIME 
ERROR (Broken BASE64 encoding detected)

-- 
Nigel Wade, System Administrator, Space Plasma Physics Group,
             University of Leicester, Leicester, LE1 7RH, UK
E-mail :    nmw@???
Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555