On 27.09.17 13:49, J Doe wrote:
1. From what I understand, “backscatter” refers to e-mails such as
non-delivery reports being sent back to the originator of a spam message.
As the originator is often a forged address, the non-delivery reports is
essentially junk data. Would this be a correct definition for the term ?
yes.
2. Is it possible to white-list the generation of non-delivery reports for
some hosts and prevent generation for all others ? For instance, if a
Gmail user attempts to e-mail me but specifies a non-existent address, I
want the non-delivery report to go them (and any other senders from
@gmail.com), but all other reports should be stopped from being sent.
at your mail server, the easiest way to avoid this problem is to reject mail
at SMTP level, either to unknown recipients (see local_recipient_maps and
smtpd_reject_unlisted_recipient), or spam (use milter or
smtpd_proxy_filter).
This way, you will not be source of backscatter - you will reject unwanted
mail immediately.
Note that local senders' mail should not be sent through milter/proxy, they
should be handled differently:
1. send through ports 587 or 465, with required authentication and ssl/tls
2. their sender addresses should be validated with smtpd_reject_unlisted_sender
or you may create list of allowed sender addresses for use check_sender_access
- apply this on ports 465 and 587
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
10 GOTO 10 : REM (C) Bill Gates 1998, All Rights Reserved!
