Mailing List SIMS@mail.stalker.com Message #6244
From: Bill Cole <listbill@scconsult.com>
Subject: Re: [OT] Content-Transfer-Encoding?
Date: Sun, 18 Jun 2000 19:43:37 -0400
To: SIMS Discussions <SIMS@mail.stalker.com>
At 8:33 AM +1000 6/19/00, Nick Quinn  imposed structure on a stream of
electrons, yielding:
>On Sunday, 18 June 2000, Nick Quinn <nquinn@acm.org> wrote:
>
>>Date: 17 Jun 2000 23:07:37 +1000
>>Message-ID: <-1250839244nquinn@acm.org>
>>From: Nick Quinn <nquinn@acm.org>
>>Subject: Re: routing domains to local users
>>Content-Transfer-Encoding: quoted-printable
>>Content-Type: text/plain; charset="US-Ascii"
>>
>>>On Saturday, 17 June 2000, Daniele Procida
>><procida@apple-juice.co.uk>
>>
>>>I have tried the line:
>>>
>>>apple-juice.co.uk =3D <local>applejuice=20
>>
>>try
>>
>><*@apple-juice.co.uk> =3D applejuice=20
>
>Any idea how the "3D" and "=20" got in there. They were not in the original.

The "Content-Transfer-Encoding" line in the headers is a MIME header that
lets mail clients know how they should decode the content (kinda obvious I
guess...) because either the originating MUA or some MTA along the way has
decided to apply some encoding to armor the original content from mangling
in transport. In this case the encoding is 'quoted-printable' which is a
rather interesting and pervasive system of minimal encoding of text to
assure that common text-handling tricks don't mangle content. In a
QP-encoded text, some characters are replaced with =xx where xx is the
hexadecimal representation of the character.  Of course, any literal '='
needs encoding (as =3D) and typically a trailing space at the end of a
line will be encoded (as =20) to make sure that no 'smart' transport agent
saves bandwidth by lopping off the (usually) meaningless space at the end
of a line.

The good side of QP is that nearly every mail agent that needs to
understand it does, and even when something goes wrong and a mailer fails
to recognize a QP-encoded message as encoded (usually because something
like a list manager hurt the headers), a human can probably read it
mostly. The bad side is that like all MIME encoding, there are a lot of
ways to screw up a message so that a client doesn't understand to decode
it, and readers are likely to say 'huh?' because the message doesn't much
look encoded.


--
Bill Cole
MAPS L.L.C. Consulting Services Group
wkc@mail-abuse.org (work)
bill@scconsult.com (personal)
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