Email Header Finger Printing

When we send an Email, the SMTP server creates a header.Study of the Mail server name reveals the OS of the server. For all this ,we have to analyze the Email Header first. The email header reveals a lot of other sensitive information about the sender including his IP.We will discuss more on this topic on other posts.
Countermeasures :
Change the mail daemon settings 

A sample Email header is shown below :

Delivered-To:XXX @gmail.com
Received: by 10.142.100.4 with SMTP id x4cs39161wfb;
        Tue, 17 Nov 2009 22:37:56 -0800 (PST)
Received: by 10.90.17.29 with SMTP id 29mr1540839agq.79.1258526174775;
        Tue, 17 Nov 2009 22:36:14 -0800 (PST)
Return-Path: 
Received: from mail15-a-ac.linkedin.com (mail15-a-ac.linkedin.com [208.111.169.137])
        by mx.google.com with ESMTP id 30si16545010iwn.121.2009.11.17.22.36.13;
        Tue, 17 Nov 2009 22:36:13 -0800 (PST)
Received-SPF: pass (google.com: domain of s-qKShvR1E_bKJbE3KpcihvgYpqS5pjeiVFRKjniEn-5Sp4jYEI5tJj_@bounce.linkedin.com designates 208.111.169.137 as permitted sender) client-ip=208.111.169.137;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of s-qKShvR1E_bKJbE3KpcihvgYpqS5pjeiVFRKjniEn-5Sp4jYEI5tJj_@bounce.linkedin.com designates 208.111.169.137 as permitted sender) smtp.mail=s-qKShvR1E_bKJbE3KpcihvgYpqS5pjeiVFRKjniEn-5Sp4jYEI5tJj_@bounce.linkedin.com; dkim=pass header.i=communication@linkedin.com
DomainKey-Signature: s=prod; d=linkedin.com; c=nofws; q=dns;
  h=Sender:Date:From:To:Message-ID:Subject:MIME-Version:
   Content-Type:X-LinkedIn-fbl;
  b=LAlAw9S8qrGPLt6phtZNvQ37jeg3yvtYlApfNHApbwizFBIvNvk2D1H6
   r7PxLyDTGK5YmRBn84TgBPD5FB0gt90r9Khp4TnNFIHyM3Sy64uMytmRj
   N4agg6dfvT5H2mO;
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple;
  d=linkedin.com; i=communication@linkedin.com; q=dns/txt;
  s=proddkim; t=1258526173; x=1290062173;
  h=from:sender:reply-to:subject:date:message-id:to:cc:
   mime-version:content-transfer-encoding:content-id:
   content-description:resent-date:resent-from:resent-sender:
   resent-to:resent-cc:resent-message-id:in-reply-to:
   references:list-id:list-help:list-unsubscribe:
   list-subscribe:list-post:list-owner:list-archive;
  z=From:=20LinkedIn=20Communication=20
   in.com>|Sender:=20messages-noreply@bounce.linkedin.com
   |Subject:=20LinkedIn=20Messages,=2011/17/2009|Date:=20Tue
   ,=2017=20Nov=202009=2022:36:03=20-0800=20(PST)
   |Message-ID:=20<2138821644.368566.1258526163419.JavaMail.
   app@ech3-cdn09.prod>|To:=20"Mr.Swaroop=20Krishnan=20S"=20
   |MIME-Version:=201.0;
  bh=HFHniqCRWqBOKiU6PXUVuudYIJ3jsx+QLmyfTd3eFzU=;
  b=SDfsYwsz/HCedRw3aFZ2JkOkKrLzzK2R1gVWv2WDNXhKtr2kM0ioAlZi
   m230bpQm4ZzCi2fwM2yyYbY8GauwKPZav6r23wyGA4hTBwHKLheSmXFI5
   /+urlA2oJGJPlWR;
Sender: messages-noreply@bounce.linkedin.com
Date: Tue, 17 Nov 2009 22:36:03 -0800 (PST)
From: LinkedIn Communication 
To: "Mr.Swaroop Krishnan S" 
Message-ID: <2138821644.368566.1258526163419.JavaMail.app@ech3-cdn09.prod>
Subject: LinkedIn Messages, 11/17/2009
MIME-Version: 1.0
Content-Type: multipart/alternative; 
 boundary="----=_Part_368565_1338859.1258526163416"
X-LinkedIn-fbl: qKShvR1E_bKJbE3KpcihvgYpqS5pjeiVFRKjniEn-5Sp4jYEI5tJj_

------=_Part_368565_1338859.1258526163416
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit