Your IP address of your computer, tablet, or phone can be found in your outgoing email headers. This can expose your physical location at the time the message is sent.
The following is an example of how to remove your device IP on your sent messages with Postfix.
main.cf, add a new task that will run header checks:
subcleanup unix n - - - 0 cleanup -o header_checks=pcre:/etc/postfix/header_checks submission inet n - - - - smtpd -o cleanup_service_name=subcleanup
Put these lines in
smtp.example.com is your own mail server domain:
/^Received:.*by smtp\.example\.com/m IGNORE /^User-Agent/ IGNORE /^X-Originating-IP:/ IGNORE
Notice we’re only taking out the
Received header where it matches your domain.
Finally, don’t forget to run
postmap before reloading Postfix for the changes to take effect.