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How to View Full Email Headers

Need to troubleshoot a bounced email? Learn how to view full email headers in Gmail, Outlook, Apple Mail, and webmail to find the cause of the problem.
Email
5 min read

Introduction

When you need to troubleshoot an email problem, like a message that bounced or a suspicious spam email, the full email headers are the best place to find the answer. Think of the headers as your email’s “digital travel log.” They contain critical, hidden information that isn’t normally visible, such as:

  • The true sender and server path.
  • The exact reason an email was rejected.
  • Whether the recipient’s server accepted the message.

This guide will show you exactly how to find and copy the full headers in most popular email clients, like Gmail, Outlook, and Apple Mail. You can then use this information to investigate the issue or provide it to our support team for faster assistance.

Prerequisites

  • An email to review.
  • An email client (either locally installed or accessed via a web portal).

Step-by-step Instructions

Viewing Headers in Desktop Clients

Mozilla Thunderbird

  1. Open the message in a new window by double-clicking on it in the list of messages.
  2. In the menu bar, select View, then Headers, and click All.
    • You may also be able to click on View followed by Message Source.

Mac OS X Mail

  1. Open the message in a new window by double-clicking on it in the list of messages.
  2. In the menu bar, click on View, then Message, then All Headers (or Raw Source on older versions of Mail).

Outlook 2016, 2013, and 2010

  1. Open the message in a new window by double-clicking on it in the list of messages.
  2. Click on the File tab, then click Properties.
  3. The Internet Headers section contains the full email header.

Viewing Headers in Webmail

Gmail Web Interface

  1. Open the message by clicking on it in the list of messages.
  2. Click on the More icon (the small line of three dots next to the Reply button at the top right of the message).
  3. On the menu that appears, click Show Original.

Horde Webmail

  1. Open the message by double-clicking on it in the list of messages.
  2. Click on Show All Headers or, on newer versions of Horde, select View Source under Other Options. View Source also is available at the top-right of the full message view.

RoundCube Webmail

  1. Open the message by double-clicking on it in the list of messages.
  2. Click on Message Source. Newer versions of RoundCube have three dots that displays More actions when you move your mouse over it. Click on More, then click on Show source.

Yahoo Mail Web Interface

  1. Open the message by clicking on it in the list of messages.
  2. Under the More menu above the message, click View Full Header.

SquirrelMail Webmail

  1. Log in to SquirrelMail and click the email containing the desired headers.
  2. In the Options: list, click View Full Header.

Windows Mail/Windows Live Mail

  1. In the list of messages, right-click on the message and choose Properties, then click on the Details tab.
  2. The headers will be shown in the section marked Internet headers for this message.

Outlook Web Interface

  1. Log in to Outlook on the web and open the specific email you want to inspect.
  2. Click the three dots (…) next to the reply, reply all, and forward icons in the top right of the message window. This is the “More actions” menu.
  3. From the dropdown menu, select View, then View message details.
  4. A new window will open displaying the full email header. You can copy the text to analyze it or forward it to someone for assistance. 

Next Steps

Now that you have copied the full email headers, here is what you can do with them.

  • Analyze the Headers Yourself: If you want to find the problem’s cause, you can use a free online “Header Analyzer” tool (like the one from MXToolbox). When you paste the headers into one of these tools, it will translate the cryptic text into a simple, human-readable report. This report will show you the email’s delivery path and, most importantly, the exact error message from the receiving server.
  • Provide Headers to Support: If our Support team asked you for these headers, copy the entire text and paste it directly into your case or chat. This gives our technicians the exact information they need to resolve your issue quickly.

Frequently Asked Questions (FAQs)

You are usually looking for a specific bounce message or status code. Look for lines that start with Status:, Diagnostic-Code:, or X-Spam-Status:. These lines often contain a 3-digit number (like 550) and a short sentence from the receiving server explaining why the email was rejected (e.g., “550 User unknown”).

This is a common tactic used in spam and phishing emails. The “From” address you see is easy to fake, like a return address on an envelope. The full headers show the actual server path (in the “Received:” lines). This allows you to see where the email truly came from and identify a fraudulent message.

Don’t worry. The process is similar in almost all email clients. Look for a “View” or “More” menu option (it might be a “three dots” icon) in the message window. The command will be named something like “View Source,” “Message Details,” “Raw Source,” or “All Headers.” Additional information should be located in your email client’s help documentation.

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