Email authentication protocol

As explained in AI for Everyday IT

An email authentication protocol is a standard that enables receiving systems to verify the authorized origin or integrity of an email message.

Email authentication protocols help receiving systems check whether a message came from an authorized sending server and whether its contents were altered. They provide useful evidence when investigating suspicious workplace email. section 7.1.3

The main checks are:

• SPF verifies that the sending server is authorized for the sender’s domain. section 7.1.3
• DKIM uses digital signatures to verify that the email was not tampered with. section 7.1.3
• DMARC tells receiving servers how to handle authentication failures. section 7.1.3

Checking a suspicious email

Copy the email’s source and headers into M365 Copilot and ask it to determine whether the message is phishing. Authentication failures can support that assessment, but users should also inspect links and sender details. section 7.1.3

Figure 7.2 Finding the source text and headers of an email in Outlook for Mac and PC

Shows where to find email source text and headers in Outlook for Mac and PC. section 7.1.3

Figure 7.3 M365 Copilot analysis of email source text

Shows an M365 Copilot analysis of pasted email source text. section 7.1.3

How AI for Everyday IT covers it

How deep it goes

Defines SPF, DKIM, and DMARC, but stops short of explaining their technical implementation.

Examples

Analyzes suspicious email source text and headers with M365 Copilot.

What it assumes

Assumes access to an email’s source and headers, while explaining protocol purposes from the beginning.

What you can do after

Diagnose phishing indicators by inspecting email source, headers, and authentication failures with M365 Copilot.

How it connects

Connects email authentication with phishing, digital signatures, email headers, and domain authorization.

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Related concepts

• SPFincludes · SPF is an email-authentication standard that lets a domain specify which mail servers are authorized to send messages on its behalf.
• DMARCincludes · DMARC is an email-authentication standard that lets a domain publish policies for handling messages that fail sender-authentication checks and receive reports about those checks.
• DKIMincludes · DKIM is an email-authentication standard that uses domain-associated digital signatures to verify message integrity and claimed origin.

This explainer was generated by Manning's knowledge graph from the text of AI for Everyday IT. The section links point to the parts of the book it draws on.