hi tarun, i am quoting my bible notes of my msc days regarding reading mail headers :
take into consideration the following mail header and read along
Received: from mail.bieberdorf.edu (mail.bieberdorf.edu [124.211.3.78]) by mailhost.immense-isp.com (8.8.5/8.7.2) with ESMTP id LAA20869 for <tmh@immense-isp.com>; Tue, 18 Mar 1997 14:39:24 -0800 (PST)
Received: from alpha.bieberdorf.edu (alpha.bieberdorf.edu [124.211.3.11]) by mail.bieberdorf.edu (8.8.5) id 004A21; Tue, Mar 18 1997 14:36:17 -0800 (PST)
From: rth@bieberdorf.edu (R.T. Hood)
To: tmh@immense-isp.com
Date: Tue, Mar 18 1997 14:36:14 PST
Message-Id: <rth031897143614-00000298@mail.bieberdorf.edu>
X-Mailer: Loris v2.32
Subject: Lunch today?
This last set of headers is the one that tmh sees on the letter when he downloads and reads his mail. Here's a line-by-line analysis of these headers and exactly what each one means.
Received: from mail.bieberdorf.edu
This piece of mail was received from a machine calling itself mail.bieberdorf.edu...
(mail.bieberdorf.edu [124.211.3.78])
...which is really named mail.bieberdorf.edu (i.e., it identified itself correctly---see Section Whatever for more on this) and has the IP address 124.211.3.78.
by mailhost.immense-isp.com (8.8.5/8.7.2)
The machine that did the receiving was mailhost.immense-isp.com; it's running a mail program called sendmail, version 8.8.5/8.7.2 (don't worry about what the version numbers mean unless you already know).
with ESMTP id LAA20869
The receiving machine assigned the ID number LAA20869 to the message. (This is used internally by the machine---it's something an administrator would need to know to look up the message in the machine's log files, but it's not usually meaningful to anyone else.)
for <tmh@immense-isp.com>;
The message was addressed to tmh@immense-isp.com. Note that this header is not related to the To: line (see Section Whatever).
Tue, 18 Mar 1997 14:39:24 -0800 (PST)
This mail transfer happened on Tuesday, March 18, 1997, at 14:39:24 (2:39:24 in the afternoon) Pacific Standard Time (which is 8 hours behind Greenwich Mean Time; hence the "-0800").
Received: from alpha.bieberdorf.edu (alpha.bieberdorf.edu [124.211.3.11]) by mail.bieberdorf.edu (8.8.5) id 004A21; Tue, Mar 18 1997 14:36:17 -0800 (PST)
This line documents the mail handoff from alpha.bieberdorf.edu (rth's workstation) to mail.bieberdorf.edu; this handoff happened at 14:36:17 Pacific Standard Time. The sending machine called itself alpha.bieberdorf.edu; it really is called alpha.bieberdorf.edu, and its IP address is 124.211.3.11. Bieberdorf's mail server is running sendmail version 8.8.5, and it assigned the ID number 004A21 to this letter for internal processing.
From: rth@bieberdorf.edu (R.T. Hood)
The mail was sent by rth@bieberdorf.edu, who gives his real name as R.T. Hood.
To: tmh@immense-isp.com
The letter is addressed to tmh@immense-isp.com.
Date: Tue, Mar 18 1997 14:36:14 PST
The message was composed at 14:36:14 Pacific Standard Time on Tuesday, March 18, 1997.
Message-Id: <rth031897143614-00000298@mail.bieberdorf.edu>
The message has been given this number (by mail.bieberdorf.edu) to identify it. This ID is different from the SMTP and ESMTP ID numbers in the Received: headers because it is attached to this message for life; the other IDs are only associated with specific mail transactions at specific machines, so that one machine's ID number means nothing to another machine. Sometimes (as in this example) the Message-ID has the sender's email address embedded in it; more often it has no intelligible meaning of its own.
X-Mailer: Loris v2.32
The message was sent using a program called Loris, version 2.32.
Subject: Lunch today?
Self-explanatory.
Picking pebbles on the shore of the networking ocean
