Corrupt pdf files, any advice.

[Julian Field]

At 11:24 28/07/2003, you wrote:
>I hope you had a good holiday.

Yes, thankyou.

>I am having a problem with pdf files corrupting when the disclaimer gets
>added to email passing through the MailScanner.
>
>RH 8.0
>Mailscanner 4.21-9
>Spamassassin/dcc/razor2
>F-prot 4.1.1
>
>Our setup is internal MS exchange 5.5 / outlook 2000 clients with
>Mailscanner as a relay to the internet.
>
>The problem only occurs when the mail is generated from MS exchange which
>sometimes encodes pdf files as quoted printable (looking on TechNet shows
>that MS exchange decides the encoding depending on the pdf file version).
>If the mail is generated with base64 the pdf file passes through correctly.
>
>I have found discussions of the problem within mailing lists of similar
>products to Mailscanner which also seem to suffer from this problem, so I
>think it must be down to the MIME::QuotedPrint perl module and the
>ambiguity of the QP standard on different OS's.
>
>http://mailtools.anomy.net/archives/anomy-bugs/2002-06/0003.shtml
>
>As a quick fix I have advised users to zip all pdf files to ensure correct
>delivery. I have also discussed the possibility of the MS exchange people
>forcing the attachment encoding to base64 but they are cautious in case
>something else breaks. I think they are unwilling to change as it all
>worked before I put in the Mailscanner relay.

I don't see that forcing Exchange to always use Base64 should break
anything at all. The whole point of encoding using Base64 is that it will
preserve the exact original attachment contents.

Fundamentally Exchange is doing it wrong by encoding a binary data file
using an encoder that is only designed to handle text files. The QP
standard is designed for encoding international characters used in text
files, and that's about it. If you want to encode binary files (such as
PDF) then use a binary encoder such as Base64.

My advice would be to force Exchange to do it correctly.
--
Julian Field
www.MailScanner.info
Professional Support Services at www.MailScanner.biz
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