Heinz said:
I would like to not only block particular emails but also send them back to
the sender so they know they've been rejected. Is that possible. Right now I
can only send them to the Junk email folder. Thanks.
How do you know the sender used their own e-mail address? You think
spammers use their real e-mail address? E-mails deliberately fake
bounced are called backscatter and this deliberate misdirection of
e-mails (through your ignorance of how SMTP works) can be reported as
spam and get you added to blacklists. You end up becoming part of the
spam problem in afflicting innocents with your misdirected bounces which
are SPAM! After all, those innocents weren't involved in the e-mail,
they didn't solicit you to send it to them, and you intend on sending
out the fake bounces as fast as you get spam so you are sending UBE
(unsolicited bulk mail) as fast as you get it.
The only time the real sender is known is during the mail session
between the sending and receiving mail servers. Every host know who is
connecting to it. If the receiving mail server rejects the e-mail, it
will notice the sending mail server DURING the mail session. The
sending mail server then sends an NDR (non-delivery report) to the
sender -- assuming that sending mail server knows who was the sender
(forwarding services won't know who is the real sender because they
would be rejecting the e-mail too late because its mail session has long
terminated with whatever was its sending mail server sending the e-mail
to that forwarding mail service). A mail server that accepts an e-mail
during a mail session but later decides the message is undeliverable
only has the return-path headers on which to identify the sender -- and
spammers (and even you) can falsify that information. That means their
out-of-mail-session NDR can also get delivered to the wrong person (and
another scheme employed by spammers so recipients start getting e-mails
back to them as undeliverable that they never sent). Any mail server
sending an out-of-session NDR should only report the non-delivery and
NEVER include the original e-mail (because that is upon what the spammer
is relying on their crap that specifies someone else as the sender who
then gets those NDRs).
Knock off the childish attitude in attempting revenge. You won't hurt
the spammer. Hell, they may even put your own e-mail address in the
From header and then you'll be blocking yourself and/or send those fake
bounces to yourself. The only entity that can accurately know who is
the sender (as regards the mail server that connected to it) is the
receiving mail server and it can only ensure a properly targeted NDR by
rejecting an undeliverable e-mail DURING the mail session with the
sending mail server. YOU are not the receiving mail server. Every
header you have in the e-mail can be altered by the sender or is of no
value to you to absolutely identify the sender. Grow up and start
employing server-side anti-spam filters on your e-mail account up on the
server and, if needed, add client-spam filtering on your host to get rid
of the crap. Fake bounces are tantamount to vigilantism. The rest of
us don't care that you feel good spewing out misdirected fake bounces.
Fake bounces makes you an irresponsible e-mail user that is actually
contributing to the problem!
