[Pan-users] Re: clearing headers?

[Duncan]

Chris Metzler <address@hidden> posted
address@hidden, excerpted below, on  Sat, 04
Oct 2008 13:20:41 -0400:

> Since the email will have attachments, that requires that the email be
> MIME-encoded; all email messages with attachments are MIME-encoded.

Note that while this is may be the only thing your client supports, there 
are attachment methods such as the older UUE (UUencoding) that don't 
require MIME.  MIME is better as it's more precisely specified (UUE just 
sort of happened, and AFAIK there's no real standard for it, only mostly 
compatible implementations), but a general statement that "all email 
messages with attachments are MIME-encoded" would be incorrect.  It may 
of course be correct within the context of your mail client only, such as 
this (added text in CAPS, parenthesis and xx indicates deletion, see 
below):

Since the email will have attachments, WITH MY CLIENT that requires that 
the email be MIME(xx-encodedxx); all email messages FROM MY CLIENT with 
attachments are MIME(xx-encoded).

The other thing is that MIME is way more than an encoding standard.  
Rather, MIME is a backward compatible message format specification 
standard which happens to include multiple encoding sub-specifications 
for use with non-plain-ansi-text when it must be sent over a 7-bit-ansi-
text-only medium such as Internet mail message standard.  The two of 
these originally described were MIME/quoted-printable, more desirable for 
content that's mostly plain-text, where reading of the raw encoded format 
may be necessary, and MIME/base64, more efficient at encoding arbitrary 
binary content.  It is however possible to represent any content in 
either encoding, if necessary.  (FWIW, it's possible to add other 
encoding specs such as yEnc to the MIME standard, and there was at least 
at one point an effort to do so with yEnc, but to my knowledge, the 
original two are the only ones that are accepted as official RFC 
standards, or even that are reasonably widely implemented.  I don't know 
the current status, but last I knew the effort wasn't making a lot of 
progress, in part because the original yEnc developer/inventor made no 
attempt to integrate with MIME early on, and it worked "well enough" 
while being so much more efficient than either UUE or MIME/base64, that 
the original spec had a big enough interest base by the time the MIME 
integration effort got underway that it sort of disincentivised things.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman