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Re: Is anyone else getting DoS'd by relay attacks?

2005-01-14 13:39:42
On Fri, 14 Jan 2005, Hannah Schroeter wrote:

Is this specified in the standards that all mail with MAIL FROM: <>
is allowed to have only one recipient?

It is specified that there is only one MAIL FROM.  A MAIL FROM: <> is
reserved for returning DSNs to the MAIL FROM.  Hence there can be
only one RCPT when MAIL FROM is <>.

Say I have this aliases file on foo.domain

      a: b(_at_)bar(_dot_)domain, c(_at_)bar(_dot_)domain

Now, I receive a bounce to a(_at_)foo(_dot_)domain, then I'd usually bundle
the forward into one SMTP transaction, and voilà, you have a MAIL FROM:
<>, with 2 RCPTs.

Yuuck.  You have a point.  However, for any DSNs entering *my* MTAs,
that situation can never legitimately occur.  For the general case, I hope
someone knows whether the RFCs address this explicitly so I don't have to go
look it up.

-- 
              Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
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