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Re: Private IP Address from Exchange
From: "Buz Dale" <buz.dale () usg edu>
Date: Fri, 1 Jun 2007 09:29:32 -0400

The mail server has to establish two-way communication with any other
mail server it talks to.  In order to do this the other server must
know it's address (or it's proxy's address and port.) That's just the
way TCP works.  UDP...not so much.

On 5/30/07, Danux <danuxx () gmail com> wrote:
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 is

Take into account, we have a CheckPoint filtering out the connections
(if you have a recommendation through this Firewall, i also has ISA
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  (EHLO smtp.soluciones.com) (
  by mta381.mail.re4.yahoo.com with SMTP; Wed, 30 May 2007 17:03:06 -0700
Received: from mailbox.soluciones.com ([]) 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;
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

Buz Dale                                buz.dale () usg edu
IT Security Specialist              1-888-875-3697 (In GA)
Office of Information and Instructional Technology
University System of Georgia
GMT -5:00

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