On July 18, 2005 at 08:15, Michael Thomas wrote:
The easy example I could find is to create a mail message
with 3000 consecutive 'a's and submit it to sendmail. It will
happily break the line for you at -- IIRC -- 2048 bytes. Nowsp
gets rid of all of those kinds of considerations and it does
it in a way that does not require *any* semantic awareness of
the underlying data. Having to have yet another piece of code
that cracks MIME, etc, seems like you're just setting yourself
up for yet another round of interoperability screwups.
I think the example is not applicable. We should not have to worry
about cases where the sender formats the message in violation of
existing standards (in this case RFC-2822).
Exactly. People who send grossly incompliant messages should expect to have
problems, and not just with DKIM.
In this specific example, I've seen MTAs that (a) Allow arbitrarily long lines
(and attempt to relay them), (b) Wrap the lines without inserting any spaces,
(c) Wrap the lines and insert some spaces, (d) Wrap the lines but insert some
prefix character, (e) Truncate the lines, and (f) Reject the message as bogus.
And the place where the line becomes to long for a given MTA also varies; the
max SMTP formally allows is 998, but I've seen limits of 998, 1024, 4000, and
probably some others I can't recall right now.
Our MTA wraps without inserting spaces by default, but can be configured to
truncate or reject. And customers do in fact both of these settings from time
to time. We used to do this at 1024 by default until someone pointed out it
really needed to be done at 998, so this also varies.
Ned