Private IP Address from Exchange

[Danux <danuxx () gmail com>]

Hi experts!!!

I dont know if it is a problem from Exchange but i thing so, let me explain...

When i send a message from my local area to yahoo, the local ip
address of my local mail box server is shown in Internet, i would like
to know if there is a way to hide the local ip address.

My client has Exchange Server SMTPSVC (6.0.3790.1830)

Here is the Header i mentioned from Yahoo ->check how 192.168.0.106 is
showed!!!:

Take into account, we have a CheckPoint filtering out the connections
(if you have a recommendation through this Firewall, i also has ISA
Server)
------------------------------------------------------------------------
> From Danux Wed May 30 17:03:04 2007
Return-Path: <danux () soluciones com>
Authentication-Results: mta381.mail.re4.yahoo.com
from=soluciones.com; domainkeys=neutral (no sig)
Received: from 145.13.115.202  (EHLO smtp.soluciones.com) (145.13.115.202)
 by mta381.mail.re4.yahoo.com with SMTP; Wed, 30 May 2007 17:03:06 -0700
Received: from mailbox.soluciones.com ([192.168.0.106]) by
smtp-out.soluciones.com with Microsoft SMTPSVC(6.0.3790.1830);
Wed, 30 May 2007 19:03:05 -0500
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----_=_NextPart_001_01C7A317.0F9CA09F"
Subject: TEST
Date: Wed, 30 May 2007 19:03:04 -0500

-----------------------------------------------------------------------
Finally its important to say that also the smtp-out.soluciones.com is
a local ip inside my network like mailbox.soluciones.com, but the
first one(smt-out.soluciones.com) doesnt get showed on Internet.

How could i hide the local ip address??????

Thanks in Advance for your help.

Microsoft says "it is the way the protocol works!!!", following the related RFC.

--
Danux, CISSP
Chief Information Security Officer
Macula Security Consulting Group
www.macula-group.com