[ietf-dkim] Updated implementation report

[John R. Levine]

>> If this is the #1 reason that verifications fail, would there be room
>> for a new canonicalization scheme, to improve verification rates?

Seems to me it would be more appropriate to add a note saying something 
like be sure your headers are all RFC 5322 compliant before signing, 
including arcana such as quoting rules in address fields, to avoid 
signature failures due to helpful relay MTAs fixing the quoting errors on 
the way through.

As far as figuring out who's doing what, it's hard to think of anything 
better than running a bunch of deliberately marginal messages through a 
variety of MTAs and see what happens.  A couple of years ago I set up a 
forwarding project, in which I asked people to set up different MTAs to 
forward mail back to me, just so we could find out about this kind of 
stuff.  The code has suffered severe bit rot but if people really wanted 
to use it, I could probably resuscitate it.

R's,
John