Limit Number of Recipients in To and Cc with Postfix for Authenticated Users
The simplest way to restrict the number of recipients in To or Cc with Postfix is the use of HEADER_CHECKS. You put in your Postfix main.cf a line like this: header_checks = pcre:/usr/local/etc/postfix/header_checks And you create a file /usr/local/etc/postfix/header_checks which contains this: /^To:([^@]*@){10,}/ REJECT Sorry, your message has too many recipients. /^Cc:([^@]*@){10,}/ REJECT Sorry, your message has too… Read More »