I have done "spamassassin -D < a_spam_message", it told me:
debug: is spam? score=5.368 required=4.3 tests=ADDR....
That's not what I asked about.. I asked what bayes score it got.. not what spamassassin score it got.
Which BAYES_ rule matched? BAYES_99??
I guess that SpamAssassin picked it up from Bayesian database. However, I sent a_spam_message from yahoo.com to my SpamAssassin box, the "hits" is only 1.6. Why?
Re-sending a message from another account is NOT the same message as far as SA is concerned. This kind of "resending" creates a message which has legitamate headers, and spam body.. it's just not the same anymore.
You need to keep in mind that SA is very observant about a message as a whole. It's not focused only on the body.
