Analyzing Email Headers

How to view headers in your email client

• GMail / GSuite / Google Workspace

  • Note that Gmail also shows a summary of SPF, DKIM, and DMARC at the top of the page when viewing the original message. This is a great quick check to make sure things are set up correctly for whomever sent you that email.

  • https://support.google.com/mail/answer/29436?hl=en

• Outlook client : https://support.microsoft.com/en-us/office/view-internet-message-headers-in-outlook-cd039382-dc6e-4264-ac74-c048563d212c

• Outlook Web Access : https://support.microsoft.com/en-us/office/view-internet-message-headers-in-outlook-cd039382-dc6e-4264-ac74-c048563d212c#tab=Web

Important deliverability headers to look for

• Return-path

• From

Resources

• Microsoft’s Message Header Analyzer

  • Great tool. Just paste your email headers in and they will get parsed out with helpful links for decoding

  • https://mha.azurewebsites.net/

• Microsoft 365 Anti-Spam Message Headers

  • Use this page to translate the O365 spam headers to diagnose why an email (that you received) was treated as spam

  • https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/anti-spam-message-headers?view=o365-worldwide

• Google email header analyzer :

  • https://toolbox.googleapps.com/apps/messageheader/analyzeheader

• LearnDMARC email header analyzer (specifically for email authentication headers including SPF, DKIM, and DMARC)

  • https://www.learndmarc.com/

• Google Article on tracing emails with headers (includes tips for all email clients)

  • https://support.google.com/mail/answer/29436?visit_id=637666119173980796-3978619276&rd=1#zippy=