Nrd said:
The following message is received:
Your message did not reach some or all of the intended recipients.
But the recipient never sent the emailthat this error refers to. What
causes this to happen?
It happens because spammers pretending to be you by using your e-mail
address as theirs and sending out their spew at e-mail addresses of
which some don't exist so those bounce back to the sender as
undeliverable. This only occurs with badly configured e-mail servers
that accept mails before checking if the mail is actually deliverable.
Because the mail session is already over between the sending and
receiving mail servers, all the receiving mail server can do when it
later finds the target account doesn't exist is to create a *new* mail
to send back to the sender, but the return-path info in the headers is
bogus (because the spammer added it as part of the DATA command in the
SMTP mail session). A mail server should check DURING the mail session
if the mail is deliverable; if not, then the receiving mail server
should reject the mail DURING the mail session. This means the
*sender's* mail server will send back an NDR (non-delivery report) to
the sender's mailbox. Sending a new mail back as an NDR outside the
mail session means only the return-path info that was added by the
sender is available, and spammer's lie. If mail servers were properly
configured to reject undeliverable mails *during* the mail session
between it and the sending mail host then you wouldn't get those bogus
NDRs due to spammers falsifying their return-path info in the headers.
Also, a relay (as would be used when forwarding e-mails) cannot itself
reject the undeliverable mail because it hasn't a clue if the mail is
deliverable or not. Only the destination mail server knows that.
You won't be able to do anything about these too-late NDR mails until
the spammer decides not to pretend to be you (i.e., until they stop
using your e-mail address as theirs). Either wait it out or get a new
e-mail address. You could try defining a rule that looks for a common
string in the headers to identify NDRs, then mark them as read and move
into the Junk/Bulk folder and use auto-archive on that folder to
automatically and permantly delete items over a couple days old. The
problem is trying to find a string that is common to NDRs.
"report-type=delivery-status" often appears in the headers but not
always. The subject line might help but often it is such a short
string, like "failure notice", that it doesn't make for a reliable
string on which to test for NDRs. You could look for "554 <comment>" in
the body of the message but a 554 status can be caused by other reasons
than an undeliverable mail, and trying to search on just "554" could
match on telephone numbers, zipcodes, or other numeric strings that have
nothing to do with an NDR status. Since there is no standardization on
the Subject or comment fields for SMTP statuses, you end up having to
look for strings long enough to help ensure a reasonable level of
uniqueness but too often the Subject and status comment fields are too
short. An NDR is one that you have to tweak over awhile after receiving
many NDRs to catch most of them without incurring false negatives.
