Gmail, Outlook, Apple Mail and More: How to View Headers in Email

February 16th, 2021

If you are having problems with message delivery, one of the first troubleshooting steps is to view headers in email. You can do this by viewing the message source. We’ll explain the basics, then teach you how to view headers in email for the most popular clients. These include Gmail, Apple Mail, Yahoo! Mail, Thunderbird and Outlook.

headers in email blog title image

How to View Headers in Email: What Is the Message Source?

The message source is the raw content of the message. It’s more than just what you see on the page when reading emails from colleagues and friends—this is just the message body. In addition to the message body that we are all so familiar with, the message source also includes the header, as well as any attachments, if present.

The header contains metadata, which is essentially data about the message, but not the content itself. This includes things like who the message is sent from, who it is being sent to, the subject, the time, and a number of other things.

When you look at the source of an email, the header includes everything from the start of the message, up until you see line breaks in the wall of text. There may be several of these, as well as a line marking the Content-Type. The message body starts after this.

The information contained in these headers can be incredibly useful for troubleshooting message delivery issues. That’s why we’re going to show you how to view headers in email.

How to View Headers in Email: What the Message Source Looks Like

Before we show you how to view message sources and how to view headers in email, it’s helpful to to first take a look at a sample layout of an email. Below is an abbreviated and edited message that we sent to a LuxSci user:

Received: via dmail-2008.19 for +INBOX;
        Tue, 3 Feb 2021 19:29:12 -0600 (CST)
Received: from abc.luxsci.com ([10.10.10.10])
	by xyz.luxsci.com (8.13.7/8.13.7) with
        ESMTP id n141TCa7022588
	for <user-999@xyz.luxsci.com>;
        Tue, 3 Feb 2021 19:29:12 -0600
Return-Path: <test@sender.com>
Received: from [192.168.0.3] (verizon.net [44.44.44.44])
   (user=test@sender.com mech=PLAIN bits=2)
   by abc.luxsci.com (8.13.7/8.13.7) with
   ESMTP id n141SAfo021855
   (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA
   bits=256 verify=NOT) for <test@domain.com>;
   Tue, 3 Feb 2021 19:28:10 -0600
Message-ID: <4988EF2D.40804@domain.com>
Date: Tue, 03 Feb 2021 20:28:13 -0500
From: "Test Sender" <test@sender.com>
User-Agent: Thunderbird 2.0.0.19 (Windows/20081209)
MIME-Version: 1.0
To: "Test Recipient" <test@domain.com>
Subject: Example Message
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Comment: Lux Scientiae SMTP Processor Message ID -
   1233710941-9110394.93984519
DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01
 Transitional//EN">


 Example HTML-formatted
email Message.

We have broken up the above example into two parts. The first part shows what it looks like when you view headers in email, and you can see things like the sender, recipient, IP addresses, date, and more. These details may be important for diagnosing email delivery issues.

The second part is a very stripped down version of the body. Normally, this is where the contents of the message would be.

How to View Headers in Email: The Techniques for Different Clients

There are many different email clients, with varying ways to check the source. This means that you will need to follow the right instructions for your client to view headers in email.

How to View Headers in Gmail

To view headers in Gmail, you need to click on the message you want to inspect. Next, click on the three vertical dots in the top right corner of the message. In the menu that pops up, click on Show original. This will open up a new tab. At the top, it displays much of the information contained in the header. You can scroll down to view the full header, as well as the message body.

How to View Headers in Outlook

To view headers in Outlook, the first step is to double-click on a message to open it. Next, click on File, followed by Properties. You will see the header information in the Internet headers box.

How to View Headers in Apple Mail

The Apple Mail app allows you to view all of your email messages’ headers by clicking on View, then Message, and then on All Headers. When you no longer need to view headers in your email messages, you can switch back to the default by clicking on View, then Message, then Default.

How to View Headers in Yahoo! Mail

To view headers in Yahoo! Mail, the first step is to open whichever email you want to inspect. On the right side of the toolbar at the top of the message, you will see an icon with ellipses. Click on these three horizontal dots. In the menu that pops up, click on View Raw Message. A new tab will open, which will show you the full source. The header will be at the top, with the message body coming after it.

LuxSci WebMail

When viewing the full content of an email message in LuxSci WebMail, click on the Headers tab at the bottom of the message display area. This will display the full header. Alternatively, you can see the message source by selecting the View Source command from the Settings and Tools drop-down menu in the upper right of the window (click on the settings gear icon).

How to View Email Headers in Mozilla Thunderbird

To view email headers in Mozilla Thunderbird, first click on the relevant message. In the top right corner, click on the button that says More. In the menu that pops up, click View source. This will open up a new window, which contains the raw message. The header will be at the top, with the body coming after.

thunderbird logo Mozilla Thunderbird (Older Versions)

When viewing the email message in question, click on the “View” menu option and select “Message Source”. You can also choose “View > Headers > All” from the menu and then expand the headers to show all of them. However, this view is not easily copied and if there are many headers, there might not be room to view them all. Your best bet is to view the message source directly. If the message is large, then the source will also be very large. In this case, the best bet is to choose “File > Save As > File” to save your message to a file (in EML format). You can then open this file with any text editor (like Notepad) and copy the headers …. the file is really just the message source.

outlook logo Outlook 2007

When viewing the message in Outlook 2007 you’ll see an “Options” area at the top of the email. In that section, on the lower right, you’ll see a circular icon that says “More Options” when you hold your mouse over it. Click this icon. You’ll then see a new window that has a section at the bottom marked “Internet Headers.”  The full headers of the message will be displayed therein.

outlook logo Outlook 2007 Web Access

When viewing the message in Outlook 2007 Web Access you’ll see an “tool bar” area at the top of the email. In that section, there is a “Message Details” icon. Click on that and the Message Details area pops up. The “Internet Mail Headers” area contains the full headers for the message.

outlook logo Outlook 2000/XP/2003

Right click on the message in its folder and choose “Options.” In the resulting pop-up window, you will see a section called “Internet headers.” The full headers of the message will be displayed therein.

outlook logo Outlook Express 6

Right click on the message in its folder and choose “Properties.” In the resulting pop-up window click on the “Details” tab, you will then see a section called “Internet headers for this message.” The full headers of the message will be displayed therein. You can also click on the “Message Source…” button to see the full raw source of the message.

mail.app logo Mail.app

With Mail.app open and your message selected, go to “View > Message > Raw Source” to access the message source. This works in both Mail.app v2 and Mail.app v3.

entourage logo Entourage 2008

With Entourage open and your message selected, go to “Message > Source” to access the message source.

eudora logo Eudora (The New One Based on Thunderbird)

For the new Eudora, which is based on Mozilla Thunderbird, you need select the message in question and go to “View > Message Source” to access the message source.

eudora logo Eudora (The Original)

For the older versions of Eudora, you need to double-click on a message to open it in a new window. Then click on the “blah blah blah” icon at the top. This will show you all of the headers for the message.

Evolution logo Evolution

Select your message and choose “View > Message Source.”

The Bat logo The Bat!

When viewing the message in question, select from the menu “View > RFC-822 Headers.” You will then see the full message headers in a “Headers” tab in the message display area.

KDE logo KDE Kmail

Select the message in question and then choose “View > View Source.”

pine logo Pine

When viewing the message in question, use the “E” command to export the message to a text file. This file will contain the full raw message source, starting with the full headers.

Pegasus Mail

Right click on the message and choose “messages headers …” Highlight the the headers and copy and paste. Alternately, just press “Control-H” when viewing the message to view the full headers.

Another option is to forward the message as an attachment — so the full headers are preserved in the forwarded message:

  • Create a new email message
  • Drag and Drop the old message into this new message.
  • In the “Drop message(s) into editor” dialog box, check the last check box at bottom of dialog box under heading “Attach or include message?” … here click “Add as attachment instead of including.”

Getting Message Headers or Source in Various Web-based Email Systems

Windows Live Hotmail

To get headers in Windows Live Hotmail, right-click on the message in your message list and then select the last option “View message source.”

AOL

Open an email in AOL mail. Click on “actions”. Choose “View Message Source.”

 

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