Reference number: CH000918
Understanding the information contained in an e-mail header.
Question:Understanding the information contained in an e-mail header.
Answer:Below is an example of what a header may look like. After this example we explain each of the major portions of the header and how to understand that data.
Delivered-To: support@computerhope.com
Received: by 1.1.1.1 with SMTP id g2cs974866bue;
Sun, 21 Jan 2007 10:40:50 -0800 (PST)
Received: by 1.1.1.1 with SMTP id o6mr53068agc.11694048335;
Sun, 21 Jan 2007 10:40:49 -0800 (PST)
Return-Path: <fakemail@yahoo.com>
Received: from web58308.mail.re3.yahoo.com (web58308.mail.re3.yahoo.com [1.1.1.1])
by mx.computerhope.com with SMTP id 9si5512040agc.2007.01.21.10.40.48;
Sun, 21 Jan 2007 10:40:49 -0800 (PST)
Received-SPF: pass (computerhope.com: domain of fakemail@yahoo.com designates 1.1.1.1 as permitted sender)
DomainKey-Status: good (test mode)
Received: (computerhope 52644 invoked by uid 60001); 21 Jan 2007 18:40:48 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
s=s1024; d=yahoo.com;
h=X-YMail-OSG:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID;
b=efbVrw8c8wqr4eSQzCeW7649jwVofY/e5lXFywYad7Q/Tns7dS5p/OZCKCZA=;
X-YMail-OSG: JF41QboVM1mJ19dW6KPDoUWVXm.95cEcw-
Received: from [1.1.1.1] by web58308.mail.re3.yahoo.com via HTTP; Sun, 21 Jan 2007 10:40:48 PST
Date: Sun, 21 Jan 2007 10:40:48 -0800 (PST)
From: Fake Mail <fakemail@yahoo.com>
Subject: Re: preeminenc zuk
To: support@computerhope.com
MIME-Version: 1.0
Content-Type: multipart/related; boundary="0-842682536-1169404848=:50690"
Content-Transfer-Encoding: 8bit
Message-ID: <112261.50690.qm@web58308.mail.re3.yahoo.com>
--0-842682536-1169404848=:50690
Content-Type: multipart/alternative; boundary="0-1777241646-1169404848=:50690"
--0-1777241646-1169404848=:50690
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Apparently-To / Delivered-To / To:
The lines that begin with Delivered-To and To: contain the e-mail address of who the e-mail is being sent to.
From:
The line that begins with From: is who sent the e-mail.
In-Reply-To:
Although not displayed on the above example (even though the subject contains Re:) the lines beginning with In-Reply-To: contains the message id of what the e-mail is being replied to. Not all e-mail servers will use this feature.
Cc:
The line beginning with Cc: contains any e-mail address that was sent a carbon copy of the message.
Bcc:
Lines that begin with Bcc: is any Blind Carbon Copy (BCC) e-mails that were also send the e-mail. Although not all e-mail programs will display this information because of privacy concerns, there are several programs that will.
Subject:
The Subject: line contains the subject of the e-mail.
Return-Path:
The line beginning with Return-Path: is what e-mail should be used if an error is encountered while the e-mail is being sent.
Received:
Lines beginning with Received: contain each of the mail servers that the e-mail has passed through to get to your Inbox. This section of the header is useful during troubleshooting e-mails that are not getting to destination because the line contains the e-mail server and IP address information, the date sent, and other useful information.
In addition to troubleshooting this is also a good indication of where an e-mail originated from. Often the first Received: (the lowest on the list) is the mail server that originated the e-mail. However, it's also easy for spammers to create a fake received making it appear that a mail simply passed through their server and that they are not the origin of the e-mail.
Message-ID:
The line starting with Message-ID: is the assignment given to the e-mail message from the first e-mail server.
Lines beginning with X-:
Anything beginning with X- is extra data that is not contained in any standard and is often used by the e-mail server or clients to provide additional information that can used with the sending and delivery of an e-mail. Below is a short list of some common X- lines you may see while viewing a e-mail header.
- X-Complaints-To: - Where to direct your complaints you have about an e-mail you received.
- X-Confirm-Reading-To: - Create an automatic response for read messages.
- X-Errors-To: The address to send an e-mail to for any errors encountered.
- X-Mailer: - Program used to send the e-mail.
- X-PMFLAGS: - Additional information used with Pegasus Mail.
- X-Priority: - Priority of e-mail being sent.
- X-Sender: - Additional information about the sender of the e-mail.
- X-Spam-zzz: - Where zzz is any number of different spam tags relating to the Spam filter on the e-mail server. Some of these include: Checker-Version, Level, Report, and Status.
- X-UIDL: - Used with e-mails distributed over POP.
Content-type / Content-Transfer-Encoding / MIME-version:
Used by MIME to know how to understand and display the e-mail in the e-mail program.
Additional information:
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