It has to do with double
negatives. Let's simplify it a bit to two domains, A and B.
The or logic would work if
you wanted to delete messages from your domains (if from contains A or
from contains B). But since you want
to take action only if it does not contain contain these items, you
have to be more circumspect about the rule.
No matter what the sending domain is,
it cannot be both A and B. The rule as you wrote it states "If it does not
contain A or does not contain B, delete the message." A message from A
will fail the first clause but pass the second clause. Since it is OR'd, the
message need pass only one clause to pass the test and be deleted. In fact,
all messages will satisfy the rule, and all will be deleted - the effect you
saw.
So you make the rule "If it does
not contain A and does not contain B, delete the message." That
way if it is either A or B it will fail one clause or the other. Since the
clauses are AND'd, the message will fail the rule and it will not be deleted.
Everything else, which comes from neither A nor B will pass both clauses and
therefore pass the test, and will be deleted.
I some ways, its sort of like trying to
suss out your incomes taxes... "If you did not answer "yes" to item 38 on page
13b, enter 462.50 on page 12 line 19 and do not skip the next
three pages..."
Thanks Dave!!!! I see the light!
Great explanation!
:)
(I
have an accountant do my taxes!)
Sharyn
