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Article: 1798
From: Anthony Howe
Date: 2007-10-28 07:47:46 -0400
Subject: Re: Milter-7bit for Windows Printable Characters

Removal...........: milters-request@milter.info?subject=remove
More information..: http://www.milter.info/#Support

Jim Hermann - UUN Hostmaster wrote:
> How can I configure or modify milter-7bit to accept Windows Printable
> Characters with decimal values 128-159?

You can't.

If there are 8-bit characters in a message, then the mail client must 
properly specify MIME headers to signal 8-bit data. For example:

	MIME-Version: 1.0
	Content-type: text/plain
	Content-Transfer-Encoding: 8bit

milter-7bit is an RFC conformance enforcement milter and recognises the 
Content-Transfer-Encoding of each MIME part and acts accordingly. You 
can only white list hosts, networks, or senders via access.db.

The RFC 2045 et al. clearly states that in the absence of the 
Content-Transfer-Encoding header, the message is assumed to be 7-bit in 
order to maintain historical backwards compatibility when many mail 
systems were not 8-bit clean and for crossing been different networks 
using different encodings, etc. BITNET, DECNET, TYMNET, etc. come to mind.

For example Hotmail system is known to be broken despite having reported 
this issue on several occasions.  They consistently send out messages 
with the "registered" symbol instead of using the HTML entity ® for 
the symbol or specify the correct MIME encoding. A 60 second fix to 
change one byte and they can't be arsed to do anything about it. So 
typically you need to specify:

	milter-7bit-connect:hotmail.com		OK

But that doesn't solve cases where someone forwards a Hotmail message 
containing the brokenness.

Anthony C Howe          Skype: SirWumpus                    SnertSoft
+33 6 11 89 73 78         ICQ: 7116561          BarricadeMX & Milters

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