As has been pointed out about a dozen times in the past week, quite a lot
of mail is received by programs that are not MUAs. They include mailing
list managers, service gateways, and other stuff. A lot of those programs
don't handle MIME at all. If MASS adds MIME sections to mail that used to
be plain text, a lot of those programs will fall over and die when they
get MASS-ized messages.
They already handle MIME.
Some do, some don't. As I said in other messages, I know of enough mail
applications that don't handle MIME that I am not comfortable writing them
all off. I also don't know how robust the applications that do handle
MIME are, and how many will break if presented with MIME sections they
weren't anticipating. This is why we need experiments.
mail is going to special gateway and should not be MIME encapsulated. The
easiest way is for MTA to check if email contains "Mime-Version:" header.
If this header is not present then MTA should assume that email is meant
to go to non-mime capable gateway and should not add MASS signature.
That strikes me as an extremely poor way to guess what the user's
intention is. All of my mail is plain text, but Pine correctly puts a
MIME-Version header on it. You can't tell from the message whether I'm
sending it to a MUA that groks MIME or some sort of application that
doesn't.
Since we have at least one proposal, Domain Keys, that doesn't have any of
this MIME breakage, I don't see any reason to prefer a design that does.
Regards,
John Levine, johnl(_at_)iecc(_dot_)com, Primary Perpetrator of "The Internet
for Dummies",
Information Superhighwayman wanna-be, http://iecc.com/johnl, Mayor
"I dropped the toothpaste", said Tom, crestfallenly.