Stopping backscatter with D_REJECT

[Todd D. Taft]

I'm running amavisd-new on a CentOS 7 system with postfix as my MTA.

I've got amavisd-new set up to run as a pre-queue test in the postfix's 
master.cf:
smtp      inet  n       -       n       -       -       smtpd
  -o smtpd_sasl_auth_enable=yes
  -o receive_override_options=no_address_mappings
  -o content_filter=smtp-amavis:127.0.0.1:10024
  -o smtpd_tls_security_level=may
smtp-amavis  unix  -    -       y       -       2 smtp
  -o smtp_data_done_timeout=1200
  -o disable_dns_lookups=yes
  -o smtp_send_xforward_command=yes

In my amavisd.conf, I've got it set to reject everything bad:
$final_virus_destiny = D_REJECT;
$final_banned_destiny     = D_REJECT;
$final_spam_destiny = D_REJECT;
$final_bad_header_destiny = D_REJECT;

However, I've noticed that somehow I'm still generating some backscatter 
on this server.  (mails from local MAILER-DAEMON going out to alleged 
spam senders).

Is there a way to stop this?

-- 
Todd D. Taft
taft at unclet.net