Analyze message headers

Analyzing message headers is a crucial aspect of managing your Microsoft 365 Messaging environment. Message headers provide valuable information about email communication, including the source and path of the message, security measurements applied, and delivery status.

In this article, we will explore how to analyze message headers in Microsoft 365 Messaging. We’ll cover the structure of message headers, extracting information from headers, and utilizing this data for troubleshooting and tracking purposes. Let’s dive in!

Understanding Message Headers

Message headers are metadata attached to each email message that is transmitted between mail servers. They contain information about the origin, route, and status of the message. Typically, the message headers are invisible to the end-users and are used primarily by mail systems and administrators.

A typical message header includes various fields such as “From,” “To,” “Date,” “Subject,” and “MIME-Version.” However, for in-depth analysis, we’ll focus on the “Received” and “Authentication-Results” fields, which hold critical details about the message’s journey.

Analyzing “Received” Headers

The “Received” header field provides insights into the path that an email message has taken. It is a series of records that represent each mail server that handled the message, in reverse chronological order. Let’s break down a sample “Received” header:

Received: from mail.example.com (mail.example.com [192.168.1.1])
by mx1.contoso.com with ESMTPS id abc123
for ; Tue, 15 Feb 2022 11:30:45 -0800 (PST)


In the above example, we can extract the following information:

1. Sender’s server: The first “Received” header indicates that the message was sent from “mail.example.com.”
2. Receiving server: The second “Received” header shows that the message was received by the server “mx1.contoso.com.”
3. Unique identifier: The “ESMTPS id” field identifies the message uniquely on the receiving server.
4. Recipient: The “for” field specifies the email address of the intended recipient.
5. Timestamp: The date, time, and timezone information indicate when the server received the email.

By analyzing the “Received” headers, you can track the path of the message, identify potential delays or issues, and verify the authenticity of the sender.

Extracting Information from “Authentication-Results” Headers

The “Authentication-Results” header field provides details about authentication checks performed on the email message. It helps validate the message’s authenticity and prevent spoofing or phishing attempts. Here’s an example of an “Authentication-Results” header:

Authentication-Results: spf=pass (sender IP is 192.168.1.1)
smtp.mailfrom=example.com; contoso.com; dkim=pass (signature
was verified) header.d=example.com;contoso.com;
dmarc=pass action=none header.from=example.com;

From the above example, we can extract the following information:

1. SPF (Sender Policy Framework): It indicates whether the sender’s IP address is authorized to send emails on behalf of the domain. In this case, the SPF check passed.
2. DKIM (DomainKeys Identified Mail): DKIM verifies the integrity of the email by validating the cryptographic signature in the message header. In this example, the DKIM signature was verified successfully.
3. DMARC (Domain-based Message Authentication, Reporting, and Conformance): DMARC provides policies to determine how receiving servers should handle emails that fail SPF or DKIM checks. In this case, the DMARC policy allowed the message to pass.

By examining the “Authentication-Results” header, you can assess the legitimacy of the email, identify any failed authentication checks, and implement necessary security measures.

Utilizing Message Header Analysis

Message header analysis plays a crucial role in various scenarios, including:

1. Troubleshooting email delivery issues: By reviewing the “Received” headers, you can identify the mail servers involved and pinpoint the potential source of delivery problems or delays.
2. Detecting email spoofing or phishing attempts: Analyzing the “Authentication-Results” header helps validate the authenticity of the sender and identify any suspicious activities.
3. Tracking email routing and delivery: The “Received” headers provide a timeline of the message’s journey, allowing you to trace its path from the sender to the recipient.
4. Implementing advanced security measures: By leveraging the information obtained from message headers, you can strengthen your email security by configuring SPF, DKIM, and DMARC policies effectively.

Conclusion

Analyzing message headers is a powerful skill that enables you to troubleshoot email delivery issues, verify the authenticity of senders, and ensure the security of your Microsoft 365 Messaging environment. By understanding the structure of message headers and extracting relevant information, you can gain valuable insights into the email communication process. Start leveraging message header analysis to enhance your email management and security practices today!