# Remove the first line of the Received: header. Note that we cannot fully remove the Received: header
# because OpenDKIM requires that a header be present when signing outbound mail. The first line is
# where the user's home IP address would be.
/^\s*Received:[^\n]*(.*)/         REPLACE Received: from authenticated-user (PRIMARY_HOSTNAME [PUBLIC_IP])$1

# Remove other typically private information.
/^\s*User-Agent:/        IGNORE
/^\s*X-Enigmail:/        IGNORE
/^\s*X-Mailer:/          IGNORE
/^\s*X-Originating-IP:/  IGNORE
/^\s*X-Pgp-Agent:/       IGNORE

# The Mime-Version header can leak the user agent too, e.g. in Mime-Version: 1.0 (Mac OS X Mail 8.1 \(2010.6\)).
/^\s*(Mime-Version:\s*[0-9\.]+)\s.+/  REPLACE $1