The following is a normal EMail message coming from a dial-in user via their ISP. Notice that it is slightly different than the previous example.
Received: from bos1c.delphi.com (184.108.40.206) by Your POP/SMTP Server's Address with ESMTP (Eudora Internet Mail Server 1.2); Sat, 21 Feb 1998 02:17:43 -0500 Received: from pobox.com ("port 2770"@[220.127.116.11]) by delphi.com (PMDF V5.1-8 #23839) with ESMTP id <01ITTJXU7PRK94MV44@delphi.com> for Valid EMail Address Withheld; Fri, 20 Feb 1998 23:29:39 EST Date: Fri, 20 Feb 1998 23:29:03 -0600 From: Valid EMail Address Withheld Errors-To: Valid EMail Address Withheld Reply-To: Valid EMail Address Withheld Subject: yoho.mid update To: Valid EMail Address Withheld Message-id: <34EE661F.3D023439@pobox.com> Organization: Al's Place MIME-version: 1.0 X-Mailer: Mozilla 4.04 [en] (Win95; I) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit
In this case, you can see that a dial-in account on pobox.com (pobox.com ("port 2770"@[18.104.22.168])) sent mail to bos1c.delphi.com (22.214.171.124) and then on to your Post Office. Notice that the way a dial-up is described here is different than that of ibm.net. Dial-up IP Addresses, are described in many different ways in EMail headers. Start learning by looking at the headers from your friends.
Also, notice Message-ID contains the sender's domain, pobox.com and ESMTP id contains the sender's Post Office domain, delphi.com.
Additionally, From, Errors-To and Reply-To contains sender's domain and address. Further, this header contains Organization which provides you with some more information about the sender.
If you have EMail addresses that are forwarded to you, this is an example of a normal EMail message arriving after being forwarded.
The routing headers define the routing of the EMail message from Post Office to Post Office. If you look at the IP Addresses, you can see how the mesage travelled through the net. Other information is also provided message headers that provide information about the location of sender.
In this case, you can see that a dial-in account on wabco-rail.com (PEIW95RMS.pei.wabco-rail.com ([172.20.12.131])) sent mail through various Mail Servers and then on to your Post Office. Notice that the way a dial-up is described here is different than that ofibm.net or pobox.com. Also, notice Message-ID contains the sender's domain, wabco-rail.com.
Additionally, From contains sender's domain and address.