How to Remove Sensitive Header Information With Postfix
/^Received:.*with ESMTPSA/ IGNORE /^X-Originating-IP:/ IGNORE /^X-Mailer:/ IGNORE /^Mime-Version:/ IGNORE /^User-Agent:/ IGNORE
Add this to
mime_header_checks = regexp:/usr/local/etc/postfix/header_checks header_checks = regexp:/usr/local/etc/postfix/header_checks
Evaluate the file and reload Postfix:
postmap /usr/local/etc/postfix/header_checks service postfix reload
Now, local IP information of your internet connection used to send emails is stripped out as well as your email client identifier and other possibly interesting information. This does not affect the deliverability of your emails.