On 4/21/2014 11:04 AM, Doug Royer wrote:
If yahoo sends out an email from list-name@yahoo, then that is where the
email is from.
Unfortunately, email is more complicated than that. There are multiple
actors, taking multiple roles. The most important one to represent
properly in the message is the author, shown in the rfc5322.from header
field.
At the top level, an author is communicating with recipients, and often
they need to be able to reply to to that author, without copying the
other recipients. Mess with the original From field and the ability to
reply is typically affected.
A mailing list is a mediator to this exchange, such that, yes, it takes
formal delivery and formally posts a new message. However the
'original' author and the 'final' recipients still treat this as an
exchange between them. The recipients are aware of the role of the
mailing list, but they do not consider the mail to be 'from' the mailing
list.
The mailing list is an originator, in formal terms, which is typically
represented by the rfc5322.sender field.
Changing the rfc5322.From field to be different than what the original
author created alters communication among the the participants.
So it would be correct to set the from/sender in the email to be
from/sender? those are two different fields.
list-name(_at_)yahoo(_dot_)com.
Why try to make it fake anything?
If you want to preserve any digital signature in the original message,
then send the original email as a mime body part in the forwarded message.
Encapsulating the original message into a subordinate message has some
appeal. It also well might have some additional attack vectors. In any
event, it's an end-to-end change, probably affecting every entity
handling the message.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net