Removing localhost from Received:

==== Required information ====
- iRedMail version: 0.8.4
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: Debian 6
- Related log if you're reporting an issue:
====

How can I remove

Received: from localhost (localhost [127.0.0.1])

From mail headers?

I have already tried adding

main.cf

header_checks = pcre:/etc/postfix/header_checks.pcre

/etc/postfix/header_checks.pcre

/^Received: from .*127.0.0.1*/    IGNORE

But there is no difference.

Thanks,

Sandy