On Wed, 13 Jan 1999 larrywyb@??? wrote:
> How can a spammers mail end up in my box with his own address in the To:
> field. IOW, I got a spam today like this:
>
> From: joeblow@???
> To: Joeblow@???
> Subject: Trillions and zillions to be made before 6:00 PM
>
>
> How does this happen
There is an important distinction between the "envelope" from and to and
the "header" from and to. The former are sometimes called the "sender"
and "recipient". The actual address that you see in the headers are very
unlikely to be the spammer's.
> and why doesn't exim reject it?
I believe that you would need a system filter set up to block messages
that have header from and to identical. You can do that, of course, with
exim, but since exim mostly deals with mail transport its options are
mostly about envelope features.
Don't try to block mail where envelope from and the header from differ.
The message that you are now reading has a header from of
"J.Goldberg@???" while it has an envelope from of
"owner-exim-users@???". There are other perfectly legitimate cases
were header and envelope froms differ (delivery reports are another). And
the standards are specifically set up to encourage this distinction.
And to the list in general:
As mentioned before, since there are more and more people running MTAs
who know little about mail transport we need a document on the basics of
mail transport. PH, maybe you should push O'Reilly again about your book.
-j
--
Jeffrey Goldberg +44 (0)1234 750 111 x 2826
Cranfield Computer Centre FAX 751 814
J.Goldberg@??? http://WWW.Cranfield.ac.uk/public/cc/cc047/
Relativism is the triumph of authority over truth, convention over justice.
--
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