header.md

main.cf

header

Restricted header_checks tables for the Postfix SMTP client.
These tables are searched while mail is being delivered.

Actions that change the delivery time or destination are not available.

smtp_header_checks

create file /etc/postfix/maps.d/header_checks

postfix_header:
  checks: []
  checks_database_type: regexp

Define own header_checks

Optional lookup tables for content inspection of primary non-MIME message headers, as specified in the header_checks(5) manual page.

Only valid action commands are supported!

postfix_header:
  checks:
    - pattern: /^Message-ID:.*<!&!/
      action: DUNNO
    - pattern: /^Message-ID:.*@(porcupine\.org)/"
      action: REJECT
      text: "forged domain name in Message-ID: header: $1"