How do I hide the originating IP address of a sender in Postfix?

Question

I run a small mail service that currently supports a few hundred users. When someone sends mail and someone looks at the source, the persons real IP is contained in, IIRC X-Originating-IP. For user privacy, I don't want their real IP to be displayed anywhere in the headers. I know this can be done as I believe most of the major webmail services do it. Is there a way to do it in Postfix for SMTP?

Thanks

Answer 1

Add the following to your /etc/postfix/main.cf:

mime_header_checks = regexp:/etc/postfix/header_checks
header_checks = regexp:/etc/postfix/header_checks

and then put the following into /etc/postfix/header_checks:

/^Received:.*with ESMTPSA/      IGNORE
/^X-Originating-IP:/            IGNORE
/^X-Mailer:/                    IGNORE
/^Mime-Version:/                IGNORE
/^User-Agent:/                  IGNORE

Don't forget to postmap this file and then reload Postfix.

(Note: It's clear this will hide even more stuff. Adapt as necessary).