Hello,

this is not strictly Postfix related, but I don't know how to get in
contact with a similar crowd of experienced folks. Please direct me to a
more suitable mailing list, it one exist.

In the last two weeks I've seen an upsurge of the rate to which spam
messages are delivered to my domain inboxes. Nothing is changed in my
quite standard configuration, thus I guess that spammers found a way to
circumvent the basic protections I have in place. Did anyone notice
something similar? What are the possible countermeasures?

I use Postfix with this simple configuration:

header_checks = pcre:/etc/postfix/header_checks.pcre
smtpd_helo_required = yes
smtpd_delay_reject = yes
disable_vrfy_command = yes
smtpd_recipient_restrictions =
        permit_sasl_authenticated
        reject_invalid_hostname
        reject_non_fqdn_hostname
        reject_non_fqdn_sender
        reject_non_fqdn_recipient
        reject_unknown_sender_domain
        reject_unknown_recipient_domain
        permit_mynetworks
        reject_unauth_destination
        permit_dnswl_client list.dnswl.org
        reject_rbl_client zen.spamhaus.org
        reject_rbl_client b.barracudacentral.org
        reject_rbl_client dul.dnsbl.sorbs.net
        reject_rhsbl_reverse_client dbl.spamhaus.org
        reject_rhsbl_sender dbl.spamhaus.org
        reject_rhsbl_helo dbl.spamhaus.org
        permit

with header_checks.pcre containing:

/^X-Delivered-To: .*@grinta\.net$/  REJECT Mail forwarding loop detected
/^(Delivered-To: .*@grinta\.net)$/  REPLACE X-$1
/^X-Spam-Status: Yes/  REJECT Looks like spam

and SpamAssassin as a SMTP proxy filter via spampd.

Thanks for any comment.

Best,
Daniele

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