Greg Wooledge wrote:
3. Thus if a receiver (be it the MTA or MUA) is verifying
whether an
email is a forgery, if the "-all" is not present in the SPF DNS
record, then the question can not be answered with 100% certainty.
MUAs cannot be receivers of mail. Only MTAs can receive mail.
Wrong. In case if you are using non-SPF aware ISP you must be able to perform
email filtering in your MUA.
You can check IP address from Received: against SPF records and move forgery to
"Spam" folder.
P.S> If your MUA can not receive mail - you will be unable to read this
message ;-)
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Andriy G. Tereshchenko
Odessa, Ukraine