diff --git a/DOC/postfix/README.header_checks b/DOC/postfix/README.header_checks
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+
+
+
+# ---
+# see: https://forum.howtoforge.de/threads/postfix-sender-blockieren-mit-wildcard-filter.9637/
+
+/^Subject: =\?big5\?/  REJECT Chinese encoding not accepted by this server
+/^Subject: =?EUC-KR?/  REJECT Korean encoding not allowed by this server
+/^Subject: ADV:/  REJECT Advertisements not accepted by this server
+/^Subject: =?Windows-1251?/  REJECT Russian encoding not allowed by this server
+/^Subject: =\?KOI8-R\?/  REJECT Russian encoding not allowed by this server
+/^Subject:.*=\?(big5|euc-kr|gb2312|ks_c_5601-1987)\?/  REJECT Language not accepted by this server as it is probably spam
+/^From:.*\@.*\.cn/  REJECT Sorry, Chinese mail not allowed here
+/^From:.*\@.*\.kr/  REJECT Sorry, Korean mail not allowed here
+/^From:.*\@.*\.tr/  REJECT Sorry, Turkish mail not allowed here
+/^From:.*\@.*\.ru/  REJECT Sorry, Russian mail not allowed here
+/^From:.*\@.*\.ro/  REJECT Sorry, Romanian mail not allowed here
+/^From:.*\@.*\.mx/  REJECT Sorry, Mexican mail is not allowed here.
+/^From:.*bounce/  REJECT Sorry, no Spam
+
+postfix reload
+# ---
+
+# ---
+# see: https://dokuwiki.tachtler.net/doku.php?id=tachtler:postfix#etc_postfix_header_checks
+
+/etc/postfix/header_checks
+==========================
+
+/^Received: from localhost/            IGNORE
+
+/^Received:.*spam\.com                 REJECT Header-Spamschutzregel RECD-1000
+
+# Weitere Beispiele
+
+if /^From:/i
+/^From:.*spam.org/                     REJECT Header-Spamschutzregel FROM-1001
+Endif
+
+if /^To:/i
+/^To:.*spam.net/                       REJECT Header-Spamschutzregel TOTO-1002
+Endif
+
+if /^Subject:/i
+/^Subject:.*Gratisaktion.*/            REJECT Header-Spamschutzregel SUBJ-1003
+Endif
+
+# Spezielles Beispiel
+/^(To|From|Cc|Reply-To):.*@spam.gov/   REJECT Header-Spamschutzregel MULT-1004
+
+/etc/postfix/body_checks:
+========================
+
+/.*spam\.(org|net|com)/                REJECT Body-Spamschutzregel TEXT-1000
+
+# ---
+
+
+# ---
+# see: https://mviess.de/sysadm/Linux/Postfix%2C%20Dovecot%20%26%20Co/Postfix%20UCE%20HOWTO%20auf%20deutsch.pdf
+# ---
+
+# ---
+# see: https://dokuwiki.nausch.org/doku.php/centos:mailserver:grundabsicherung_von_postfix
+# ---
+
+
+# ---
+# see: https://dokuwiki.nausch.org/doku.php/centos:mail_c7:spam_5
+# ---