Examining the headers of the email will require you to locate the appropriate setting in your email client. Usually by default the email reader will show the basic headers indicating email addresses to, from, and to be replied to, and the date. The complete headers mentioned earlier, including the servers passed through and times involved are available through viewing options which differ from program to program. In many cases there are "headers" options in the "view" menu, and in others there are "options" associated with each email which will show you the full headers. You will need to consult the manual or help files for your email program to find out how to access these.

Having accessed the full headers of your email, you will see something like the following:

	Received: from pmta07.mta.provider.net (bigiplb-dsnat [172.16.0.19])
	 	by imta14.mta.provider.net (Postfix) with ESMTP id A73751857A6
		for ; Thu, 12 May 2005 08:30:03 -0700 (PDT)
 	Received: from c3po.sender.com (205.210.42.42 [205.210.42.42])
		by pmta07.mta.provider.net (EON-PMTA) with ESMTP id 9DAC2847
		for ; Thu, 12 May 2005 08:30:03 -0700
	Received: from localhost (localhost [127.0.0.1])
		by c3po.sender.com (Postfix) with ESMTP id 15E108B74F
		for ; Thu, 12 May 2005 11:30:01 -0400 (EDT)
	Received: from c3po.sender.com ([127.0.0.1])
		by localhost (c3po.sender.com [127.0.0.1]) (amavisd-new, port 10024)
		with ESMTP id 15063-07 for ;
	 	Thu, 12 May 2005 11:30:01 -0400 (EDT)
	Received: from [192.168.1.26] (office.sender.com [66.207.199.34])
	 	by c3po.sender.com (Postfix) with ESMTP id 04B9E8B749
		for ; Thu, 12 May 2005 11:30:01 -0400 (EDT)
	Message-ID: <42837675.20407@sender.com>
	Date: Thu, 12 May 2005 11:29:57 -0400
	From: test@sender.com
	Reply-To: test@sender.com
	Organization: Internet Company
	User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103)
	X-Accept-Language: en-us, en
	MIME-Version: 1.0
	To: account@recipient.ca
	Subject: example
	Content-Type: text/plain; charset=ISO-8859-1; format=flowed
	Content-Transfer-Encoding: 7bit
	X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at sender.com
		

If you want to know how to find this out for yourself, the principal parts of the headers you are interested in are the domain name in the from and reply-to headers, and the headers towards the top which each start with "received."