I experience certain problems with the messages I receive from
poorly configured `sendmail' installations. These problems take
place only for the messages that have 8-bit characters (my native
alphabet, for instance). `sendmail' which relays such messages is
set not to allow 8-bit characters to be transferred in SMTP session.
So, it converts these messages into base64 and adds a
"X-MIME-Autoconverted:" field into headers, where it specifies that
the message was converted from 8bit to base64. But it does not touch
"Content-Transfer-Encoding:" field! Exim, being 8bit-transparent,
does not do anything to such messages because they are certainly
properly formed. As the result I get base64-encoded messages that
are treated like plain 8bit ones by MTUs, making these messages
unreadable without appropriate filtering or decoding. But if I had
`sendmail' on my side, it would trigger on this non-standard field
and unwrap a message back into 8bit, bringing the real content in
compliance with "Content-Transfer-Encoding:" field.
After such a quirky intro, here is my question :)
How can I process "X-MIME-Autoconverted:" field with Exim? Should I
parse the header and change "Content-Transfer-Encoding:" to the
value from the parsed "X-MIME-Autoconverted:" field? Hope, there is
a better way!
