I have a central mail relay server and other 4 servers that send mail through the first one.
When I send a mail from one of the "slave" servers, the outgoing mail arrives to the destination with some references to the original server that originated it.
For example, the final email includes the relay:
Received: from mail.myserver.com (mail.myserver.com. [178.63.10.61])
But also the originating server:
Return-Path: <mywebsite@www1.myserver.com>
I'd like to hide every reference to the second one, and show only the hostname of the final relay.
I've been already able to hide some of the references using regular expressions with header_checks, but some others like the Return-path seem to be un-erasable.