Matthew Elvey <matthew(_at_)elvey(_dot_)com> wrote:
SPF on its own, as currently written will have no medium or long term
impact on spam other than joe-jobs and bounces and bandwidth.
True. RMX clearly stated this from the start.
Q: Is the cost of deploying RMX (etc.) worth it, given those constraints?
A: Ask the people who've had experience implementing it.
I think the folks who just want to protect HELO or MAIL FROM have
failed to explain why From: is not feasible to protect.
Messages get forwarded by third parties (e.g.this mailing list).
The MTA/DNS of the "From:" domain doesn't know who in that domain has
subscribed to what mailing list. And it's impractical to distribute
that information outside of the mailing list.
This issue highlights more implicit assumptions and field
overloading in SMTP.
Alan DeKok.