What is happening with E-mail Headers?
E-mail header information has been added to Message Log Details.
Administrators will now be able to view and download email message headers directly from the message detail window.
How do I access the E-mail Header Information?
E-mail header information is accessed from the Message Log Details window of a given message.
- Navigate to the Log Search page
- Perform a search
- Click the Details button (under Actions column) for a given message
- Select either Preview or Download
Preview : Display email header information on the screen Download : Download a copy of the email headers (File is downloaded as a zipped EML file. No message body or attachments are included)
There is currently a known limitation where the 'download' button only works for a local administrator (ie. organization admin). Partner admins can still preview header information.
How can I use the E-mail Headers to Investigate an Email?
Headers contain many helpful pieces of information.
Here are a couple examples, however many other fields can also be valuable.
1. A valuable field in the headers will be the "Authentication-Results:" field.
This can be used to evaluate email authentication results when trying to determine the legitimacy of an email, or to try to understand why one was blocked.
- spf = spf result. typically pass/fail
- smtp.mailfrom =envelope sender domain (what SPF authenticates)
- Note: For SPF alignment (for purposes of DMARC) this field must match header.from value
- dkim = dkim result. typically pass/fail
- header.d= domain value (d=) from the DKIM signature
- Note: For DKIM alignment (for purposes of DMARC) this field must match header.from value
- header.s = selector value (s=) from the DKIM signature
- dmarc = dmarc result. typically pass/fail
- header.from = from header domain (what DMARC authenticates)
- header.policy = DMARC policy from DNS (none/quarantine/reject)
2. Another valuable field in the headers is the "Reply-To:" field.
When the Reply-To address is unrelated to the sender, this can be an indication of malicious intention (especially if the reply-to domain is a public email domain such as Gmail, Yandex, etc)
Note: End users often don't realize when the recipient address of their reply message is different from the sender address of the email that they received.