After some trial and error I figured out the correct regular expression for what I wanted.
Originally Posted by uxbod
In "/opt/zimbra/conf/postfix_header_checks.in" I added:
Now when ZCS sees a header like this:
/^Received: from .+\..+\.domain\.com .+(by zimbra\.domain\.com .+) / REPLACE Received: $1
It will rewrite it as:
Received: from host.zone.domain.com (host.zone.domain.com [192.168.20.2]) by zimbra.domain.com (Postfix) with ESMTP id 5870116BD472 for <email@example.com>; Sun, 13 Apr 2008 09:04:22 -0400 (EDT)
So you can eliminate a potential privacy breach by stripping host name, zone and IP's from internal mail clients outgoing messages by using postfix header_checks.
Received: by zimbra.domain.com (Postfix) with ESMTP id 5870116BD472 for <firstname.lastname@example.org>; Sun, 13 Apr 2008 09:04:22 -0400 (EDT)