Tony Finch writes:
On Wed, 21 Nov 2007, Arnt Gulbrandsen wrote:
But 3461 (bottom two paragraphs of page 13) says any message can have
<> as sender when it reaches the recipient.
Null return paths have never been particularly consistent or clearly
scoped :-) But still, RFC 3461 doesn't say that arbitrary programs
can send email from <> because they think it would be neat.
As I read it, it says that arbitrary SMTP clients may send email from <>
because the sender of the message doesn't want to be told about the
fate of the message. IMO that's much the same thing.