On Wed, 28 Oct 1998, Lee Bradshaw wrote:
> Most things are working, but failed delivery messages from work don't
> seem to have proper address information. Fetchmail/exim at home choke
> trying to retrieve this message. Any suggestions? I can provide more
> information if necessary.
> reply from alantro.com, From: header says mailer-daemon, but envelope from
> doesn't seem to exist.
This looks like somebody's software having trouble with null senders,
which are the standard usage on bounce messages. Failing to handle null
senders is alas all too common.
> 1998-10-28 11:44:22 0zYbW2-00005M-00 <= <> R=0zYbW2-00005G-00 U=mail P=local S=1485
>
> ### ^^ Who is sending this message?
That just confirms that the envelope sender is null, as it should be.
Here is the relevant text from RFC 1123:
5.2.9 Command Syntax: RFC-821 Section 4.1.2
The syntax shown in RFC-821 for the MAIL FROM: command omits
the case of an empty path: "MAIL FROM: <>" (see RFC-821 Page
15). An empty reverse path MUST be supported.
[...]
5.3.3 Reliable Mail Receipt
When the receiver-SMTP accepts a piece of mail (by sending a
"250 OK" message in response to DATA), it is accepting
responsibility for delivering or relaying the message. It must
take this responsibility seriously, i.e., it MUST NOT lose the
message for frivolous reasons, e.g., because the host later
crashes or because of a predictable resource shortage.
If there is a delivery failure after acceptance of a message,
the receiver-SMTP MUST formulate and mail a notification
message. This notification MUST be sent using a null ("<>")
reverse path in the envelope; see Section 3.6 of RFC-821. The
recipient of this notification SHOULD be the address from the
envelope return path (or the Return-Path: line). However, if
this address is null ("<>"), the receiver-SMTP MUST NOT send a
notification. If the address is an explicit source route, it
SHOULD be stripped down to its final hop.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
--
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