Za'mbori, Zolta'n wrote:
If Aardvarks.example.com will be the MAIL FROM than MTA doing white-list
filtering at the SMTP level will refuse this email even the white-list
contains the email address of Bob.
So our scenario goes like this: Chris wants publisher Aardvarks to send an
article to Bob. Chris is in Bob's whitelist, but Aarvarks is not. Should the
message from Aardvarks be delivered to Bob on the basis that it was requested
by Chris, although not sent *by* him as such? In other words, should the
whitelisting be transferrable? If Bob has authorised Chris to send mail to
him, can Chris then share that authorisation with Aardvarks? If so, is the
authorisation a one-off thing, or a permanent thing? And can Aardvarks then
share the authority with its "business partners"?
You can probably see where this is going. It's the situation that we have now
with email addresses. I can create a single-use email address (like the one
I've used for subscription to this list), but I can't control its
dissemination and subsequent use. The best I can do is retire an address when
it becomes abused beyond its worth. If I had a strong LMAP-like means of
verifying sender addresses, then I could restrict incoming addresses to use
by particular senders, but the senders could not easily share their authority
to send. Anything more subtle than those two policies will be difficult to
implement. Not impossible, but certainly complex.
So let us assume that Chris is NOT authorised to share his mail-sending
authority with third parties. Acting on Chris' request, Aardvarks.example.com
finds itself unable to send mail to Bob, because Bob's mail policies reject
mail from unknown parties. What can Aardvarks do about this? One possibility
is to mail the article to Chris instead, saying, "we were unable to deliver
this article to Bob as you requested. Please forward it to him with our
compliments, and suggest that he add Aardvarks to his mail white-list if he
wishes to receive forwarded articles from us more conveniently in future."
If Chris is unable to forward the article to Bob himself, then he never had
the authority to request the mailing in the first place.
Regards,
TFBW
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