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Re: Fixing graylisting [was TBR]

2007-11-17 08:10:14

SM <sm(_at_)resistor(_dot_)net> wrote:
At 18:30 16-11-2007, John Leslie wrote:

It may be worth noting that sender address rewrite should not
be done when forwarding a message via TBR.

That would rule out using SPF then.

(I can't offhand think of a reason you'd actually want to...)

SPF recommends using SRS (Sender Rewriting Scheme) for forwarding.

   As you said, "recommends". (I don't see how that "rules out"

   Whether you apply SPF processing on an incoming email really
doesn't matter to TBR. The only case of interest is where you
receive a TBR message (which, of course, you can only do if your
MTA advertises TBR) _and_ pass it to the next hop via TBR (which
can only happen if that MTA advertises TBR). In that case,
rewriting the RFC2821MailFrom is a bad idea.

   I doubt there's any implementation of SPF that doesn't allow
you to separate SPF processing from RFC2821MailFrom rewriting.
If there is, _that_ is a bad idea. There are other things that
can be broken by indiscriminate RFC2821MailFrom rewriting.

   This issue emphasizes how complex things become if we apply
patches to try to make our pet ideas do things they were not
originally designed to do.

John Leslie <john(_at_)jlc(_dot_)net>