Overview

When an email message is first created, email systems add technical information about the message to a hidden section known as the internet header or full header. This information includes technical details including, but not limited to, the author of the message and the software used to compose the message. As the message travels to to the end recipient, the message logs additional information, including which specific email servers the message passed through on its way to the recipient. These details can identify problems with the message or help discover the sources of unsolicited commercial messages, spam, and suspected phishing attempts.

How to view message headers

• Outlook 2016 and newer (Windows Operating System)
  1. Select the message so that it opens in a new window.
  2. Select the File tab.
  3. Select Properties.
  4. Header information appears in the Internet headers box.
• Outlook 2016 and newer (Macintosh Operating System)
  1. Select the message so that it opens in a new window.
  2. Right-click and select View Source.
  3. Header information appears in the Internet headers window.
  4. Outlook on the Web. (Outlook Web Access-OWA/Office 365)
  5. Select the message so that it opens in a new window.
  6. At the top right area of the message, select the down option next to Reply All (looks like a vertical bar followed by a downward pointing 'V').
  7. Select View message details in the popup menu.
  8. Header information appears in the Message details window.
• EliApps
  1. Select and open the email you want to check the headers for.
  2. Next to the Reply button, select the Down arrow.
  3. Select Show original.

What to do with the Message Headers

View the message headers to analyze message details, including the true sender of the message, specific servers the messaged traveled through to reach your inbox, and the length of time the message took to travel from each server. Individuals can copy and paste the full headers into a free header analyzer tool (one example is MX Toolbox) to view detailed information.

If you need to report a message you believe to be a spam or a phishing attempt, you can take the following actions depending on your mail system:

Office 365 Email

• Follow the steps in the Report Spam and Phishing article.

EliApps

• Follow the steps in the Report Spam and Phishing article.

 

Related Articles

• Microsoft 365: Safe Links
• Microsoft 365: Safe Attachments in Microsoft 365
• Microsoft Defender (Safe Links, and Safe Attachments) Information and FAQs
• Blocking or allowing a sender in Outlook
• Best practices for managing spam and phishing emails

Need Further Assistance?

Contact the ITS Help Desk

• Phone: 203-432-9000
  • Hours: Monday–Friday, 8:00 a.m.–5:00 p.m. (Escalation support remains available after hours, on weekends, and during holidays for time-sensitive, health, life, or safety critical issues).
• Schedule a Callback
• Visit an in person support center