North American Network Operators Group
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Re: Clueless anti-virus products/vendors (was Re: Sober)
- From: Douglas Otis
- Date: Thu Dec 08 13:09:36 2005
On Dec 8, 2005, at 2:18 AM, Michael.Dillon@btradianz.com wrote:
It seems reasonable to design a mail system so that notifications
are sent back to the originator of the message when there is a
problem somewhere along the delivery chain.
Agreed. The alternative would be more like instant messaging.
It seems very UNreasonable to send notifications to random
destinations that have nothing to do with originating the message
in question.
It is also unreasonable to assume the return-path can always be
associated with the sending MTA.
The crux of the matter is that if you don't KNOW the true source of
the message, then you cannot return a DSN. You can go through the
motions, but then you are originating SPAM (UBE), not returning DSNs.
When accepting messages from anonymous sources, seldom does one know
the source.
Should you be accepting any mail at all from SMTP servers that you
do not know and trust because of prior contact, i.e. negotiating an
email peering agreement?
Making email a closed system would dramatically change who can send
messages and how email would work. The safest place to decide
whether a DSN is legitimate is by the MTA located by the return-
path. Use of BATV allows the return-path MTA to immediately refuse
DSNs determined to be illegitimate. Immediately, the back-scatter
problem would be substantially resolved and no RFC need to be
changed, and the integrity of email delivery would not suffer. This
would also close the "back-door" used to evade black-hole lists.
-Doug
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