Bloqueando SPAM no e-mail

em /etc/postfix/body_checks.pcre adicione

/lotofácil/     DISCARD
/Cidadania Italiana/     DISCARD

Rode o comando

postmap /etc/postfix/body_checks.pcre

e reinicie o postfix

service postfix restart

pode testar assim

postmap -q "lotofácil" pcre:/etc/postfix/body_checks.pcre

ou criando um arquivo assim

To: test@seudominio.com.br
Subject: sendmail test two
From: test@seudominio.com.br

And here goes the e-mail body, test test test.. lotofácil

e rode o comando

sendmail -vt < mensagem-de-teste.txt

Referências

• https://www.cyberciti.biz/faq/howto-blacklist-reject-sender-email-address/
• http://serverfault.com/questions/728641/blacklisting-tld-in-postfix
• http://www.linuxquestions.org/questions/linux-server-73/how-to-reject-addresses-by-tld-in-postfix-678757/
• https://www.linuxbabe.com/mail-server/block-email-spam-check-header-body-with-postfix-spamassassin
• https://serverfault.com/questions/667268/postfix-2-9-or-sendmail-outgoing-spam-prevention-check-if-sender-exists

https://clients.javapipe.com/knowledgebase/132/How-to-Test-Sendmail-From-Command-Line-on-Linux.html