On Sun, 30 Jan 2011, Stuart D. Gathman wrote:
The forwarding you are concerned about is something only the
recipient can know about or initiate. Why would a sender want a message
rejected if the recipient happened to forward it to another mailbox?
Usually, they don't. Except for the case of the VERP/exists/magic-DNS
hack, deploying "/all" would be a reckless act.
But not a senseless one. A (non-VERP) sender who publishes "/all" is not
trying to break forwarding; he would be *accepting* the breakage of
forwarding in return for a much higher efficacy in supressing forgeries.
And again, the key advantage of "/all" is not that many senders will use
it. It's to ensure that recipients don't accidentally assign rawfail
semantics to "-all", a problem that has ruined SPFv1 by deterring senders
from publishing it.
Giving senders the ability to use "/all" to tell a normally-cautious
validator to go wild, is just a bonus.
---- Michael Deutschmann <michael(_at_)talamasca(_dot_)ocis(_dot_)net>
Sender Policy Framework: http://www.openspf.org [http://www.openspf.org]
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