root@ina:/etc/postfix
# cat generic
/^(.*)@ina\.leonerd\.org\.uk$/ $[email protected]

root@ina:/etc/postfix
# cat main.cf 
myhostname = ina.leonerd.org.uk
myorigin = ina.leonerd.org.uk
mydomain = leonerd.org.uk

# Rewrite mailer-daemon -> postmaster -> root -> leo, etc.
# TODO: Does this even do anything? alias_maps is for local delivery, of which we have none
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases

relayhost = mail.leonerd.org.uk
smtp_generic_maps = regexp:/etc/postfix/generic

# No local delivery thus forcing all mail to go to relay
mydestination = 
local_transport = error:local delivery is disabled
inet_interfaces = loopback-only


root@ina:/etc/postfix
# mail root
Subject: Test with regexp generic map

Cc: 
Null message body; hope that's ok


root@ina:/etc/postfix
# tail /var/log/mail.log 
Oct 21 16:06:25 ina postfix/pickup[5945]: 3B7E7645F: uid=0 from=<root>
Oct 21 16:06:25 ina postfix/cleanup[5950]: 3B7E7645F: message-id=<[email protected]>
Oct 21 16:06:25 ina postfix/qmgr[5946]: 3B7E7645F: from=<[email protected]>, size=326, nrcpt=1 (queue active)
Oct 21 16:06:25 ina postfix/smtp[5952]: 3B7E7645F: to=<[email protected]>, orig_to=<root>, relay=mail.leonerd.org.uk[81.187.167.226]:25, delay=0.56, delays=0.2/0.01/0.07/0.28, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as D04FF1BDC3)
Oct 21 16:06:25 ina postfix/qmgr[5946]: 3B7E7645F: removed



######

Return-Path: <[email protected]>                                                                                      
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on cel.leo                                                      
X-Spam-Level:                                                                                                           
X-Spam-Status: No, score=-2.9 required=4.0 tests=ALL_TRUSTED,BAYES_00                                                   
        autolearn=ham version=3.3.2                                                                                     
X-Original-To: [email protected]                                                                                      
Delivered-To: [email protected]                                                                                               
Received: from ina.leonerd.org.uk (ina.leo [192.168.42.27])                                                             
        by cel.leonerd.org.uk (Postfix) with ESMTP id D04FF1BDC3                                                        
        for <[email protected]>; Fri, 21 Oct 2011 16:06:16 +0100 (BST)                                                
Received: by ina.leonerd.org.uk (Postfix, from userid 0)                                                                
        id 3B7E7645F; Fri, 21 Oct 2011 16:06:25 +0100 (BST)                                                             
To: [email protected]                                                                                                 
Subject: Test with regexp generic map                                                                                   
Message-Id: <[email protected]>                                                               
Date: Fri, 21 Oct 2011 16:06:25 +0100 (BST)                                                                             
From: root <[email protected]>