Removing Received field in mail header with Postfix

If you want to hide email source, you can easily remove Received field in mail header using header_checks.

Add to postfix configuration file main.cf line

header_checks = regexp:/etc/postfix/header_checks

File /etc/postfix/header_checks will contain
/^Received:/ IGNORE

More examples can be found at http://www.posluns.com/guides/hedrem.html