Get Important Email Info by Viewing the Entire Header

There's more to know than just subject line, sender, and date

Smartphone in space with email envelopes coming out from it
Busakorn Pongparnit / Getty Images

What you probably think of as an email header contains the "to" and "from" addresses, as well as the date and subject line. But, that's really just the tip of the iceberg. An entire email header contains much more information that can be valuable in certain situations, such as troubleshooting or thwarting scammers.

The Role of Email Headers

Every email consists of two parts: the header and the body of the message. Email headers include behind-the-scenes information that controls the transmission of the message and identifies metadata. In addition to the data you normally see, the header includes such information as the path the email takes, the servers it passes along the way, the time it does so, and the message priority.

Most people never need to view the entire header of an email. However, when troubleshooting an email problem, a technician may ask you to send the complete header for evaluation.

Additionally, you may be able to use it to identify a spam sender or verify that the email is a spoof or phishing attempt. Phishing attempts are malicious attacks that attempt to have your hand over private or sensitive information to an individual masquerading as an authentic source (such as your bank or other financial institution). Examining headersĀ can be a powerful way of identifying such scams and keeping yourself safe.

How to View an Email Header

To the untrained eye, email headers are lengthy (sometimes longer than the body of the message) and complex. But, most email clients and email web pages provide a way for you to display email headers. Each email program has its own method for viewing the entire header of a message. The instructions below show how to view the header in Gmail; check the documentation for other providers to learn how to view headers in those programs.

  1. Open the Gmail message.

  2. In the upper-right corner, select the menu (three-dot) icon. From the menu, choose Show original.

    Show original menu item in Gmail
  3. You'll see some basic information at the top, followed by the full header at the bottom. Scroll down to view more.

    Email header information
  4. Review the following information to understand what you're seeing in the full header.

Understanding an Email Header

Email headers can appear as long complex blocks of text, but knowing what to look for can help you search them like a professional. Here are some of the bits of information you'll find:

  • Content-Type: Notes whether the message is in HTML or plain text.
  • Date: When the message was composed.
  • Delivery Date: When the message was received by your mail server.
  • From: Who sent the message.
  • Received: All the servers the message was sent through.
  • Return-Path: Where a reply to the message will be sent.
  • Subject: The message subject.
  • To: Who the message was addressed to.
  • X-Originating-IP: The IP address from which the message was sent.
  • X-Spam: Spam information generated by your email service.

Email header information can be forged. In particular, fields such as From can be easily manipulated. Only sections containing the keyword Received should be fully trusted.