RFC 3461, "Simple Mail Transfer Protocol (SMTP) Service Extension for Delivery Status Notifications (DSNs)", January 2003Source of RFC: IETF - NON WORKING GROUP
Area Assignment: app
Errata ID: 4222
Status: Held for Document Update
Publication Format(s) : TEXT
Reported By: Ned Freed
Date Reported: 2015-01-06
Held for Document Update by: Barry Leiba
Date Held: 2015-03-01
Section 5.1 says:
(b) If an SMTP client issues a RCPT command containing any valid NOTIFY and/or ORCPT parameters, a conforming SMTP server MUST return the same response as it would to the same RCPT command without those NOTIFY and/or ORCPT parameters. A conforming SMTP server MUST NOT refuse a RCPT command based on the presence or absence of any of these parameters.
It should say:
(b) If an SMTP client issues a RCPT command containing any valid NOTIFY and/or ORCPT parameters, a conforming SMTP server MUST NOT alter its response solely based on the use or nonuse of these parameters. A conforming SMTP server MUST NOT refuse a RCPT command based on the presence of any of these parameters for anything other than reasons of local policy.
The text as written effectively precludes using the content of the ORCPT or
NOTIFY parameters in implementing local filtering policies in general and
AS/AV policies in particular. If, for example, a particular ORCPT value
is known to associated with a source of spam, rejecting messages on that basis
at RCPT TO time should not be prohibited. Similarly, a site may place a high
priority on avoiding the possibility of blow-back spam associated with the
use of NOTIFY=SUCCESS; it should again be possible to reject messages
requesting success receipts as a matter of local policy.