What Is an Email Header Understanding Its Purpose and How to View It in Outlook

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    Understanding email headers is one of the most necessary email marketing terms that can contribute to the improvement of your email deliverability and is crucial for effectively managing email campaigns or transactional communications. 

    It contains technical aspects and details of the senders, including information of the receiver, the subject, and the time it was sent.

    For many email service providers, reviewing email headers is quite straightforward. However, in our experience as email deliverability experts, we’ve noticed that many users find it difficult to view email headers in Outlook.

    In this blog, we’ll take a deeper look about email headers, what they are, their purpose, and how to view them in Microsoft Outlook.

    What is an Email Header?

    An email header is a part of an email message that contains technical metadata, such as the sender’s and recipient’s addresses, subject line, sending date and time, and information about how the message traveled through mail servers. This header metadata tells email systems where the message originated, its destination, and how it arrived at its current location.

    The technical details required for routing and processing the email are contained in the header, while the body of the email contains the actual message and attachments. The header also includes various verification data to help determine whether the email is authentic and assess its potential threat level.

    Key Components of an Email Header

    Here are some of the key elements you can find in an email header:

    1. From: The email address of the sender.
    2. To: The email address of the recipient.
    3. Subject: The title or subject line of the email.
    4. Date: The timestamp of when the email was sent.
    5. Message-ID: A unique identifier for the email, allowing the email client to track the message.
    6. Received: Information about the mail servers that processed the email along its path to the recipient.
    7. Return-Path: The address used for bounce messages (if an email cannot be delivered).
    8. Authentication Results: Information on whether the email passed various security checks, such as SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance).

    These components help email systems verify the authenticity of messages and route them appropriately, and they are essential for troubleshooting and improving email deliverability.

    Importance of Email Headers for You

    Most email users mistake email headers as background data. However, the information within the email headers can be crucial for the following pursuits. 

    Diagnosing Email Delivery Issues

    Email headers are especially useful when you are unable to receive an email message or if it was moved to a spam folder. If an email ends up in the spam folder, examining the email header could help you understand why (e.g., missing authentication headers, using a blacklisted IP address, etc.).

    Validating Email Legitimacy

    Email headers can help differentiate between real and fake emails. By examining details such as the sender’s domain, the path the email took to get to you, and a collection of authentication results, it’s possible to determine whether an email is legitimate or a phishing attempt.

    Enhancing Email Security

    Headers contain key information relevant to the processing and verification of an email, and they can help identify malicious emails, strengthening protection against potential breaches.

    Monitoring Email Performance

    Knowing exactly what happened, when, and how emails were delivered makes email headers an important source of information for organizations and marketers.

    How to View an Email Header in Outlook

    While email headers are hidden by default in Outlook, they can be accessed easily through a few steps. Viewing the email header in Outlook allows you to access the detailed metadata of an email to troubleshoot delivery issues, investigate potential phishing attempts, or verify sender information. And in some ways, it can help you identify if there are misconfiguration issues

    Step-by-Step Guide to Viewing Email Headers in Outlook

    For Outlook Desktop (Windows):

    1. Open the Email: Start by opening the email whose header you want to inspect.
    2. Click on the Three Dots: In the email window, click on the three dots (More options) located in the upper-right corner of the email.
    3. Select ‘View Message Source’: From the dropdown menu, click on View Message Source. This will open a new window containing the full email header.
    4. Review the Header Information: The email header will be displayed, and you can scroll through it to review the sender’s information, routing path, authentication results, and more.

    For Outlook Web (Office 365 or Outlook.com):

    1. Open the Email: Go to your inbox and open the email you want to examine.
    2. Click on the Three Dots: In the upper-right corner of the email message, click on the three dots (More options).
    3. Select ‘View Message Source’: Click on View Message Source from the options presented. A new window will open showing the email header in a text format.
    4. Analyze the Header: The header details will appear in a text block. Here you can analyze the various elements like the sender, recipient, and routing information.

    For Outlook on Mac:

    1. Open the Email: Open the email whose header you want to inspect.
    2. Click on ‘View’: On the top menu, click on View and select Message Source.
    3. Review the Header Information: The email’s header will open in a new window, and you can review all the detailed metadata of the message.

    What to Look For in the Header

    Once you have accessed the email header, there are several key pieces of information you should focus on:

    1. Received Fields: Useful for tracking the path of the email and identifying delays or issues during routing.
    2. Authentication Results: Look for any mentions of SPF, DKIM, and DMARC results. If these fields show failures or issues, the email may not have passed authentication and could be flagged as spam.
    3. Return-Path: This shows the email address used for bounce-back messages. If the return path seems suspicious or doesn’t match the sending domain, the email may be fraudulent.
    4. Message-ID: Each email has a unique Message-ID that allows email clients to track and reference the message.
    5. Sender Information: Ensure that the “From” field matches the sender’s domain. If it doesn’t, or if the domain looks suspicious, the email may be a phishing attempt.

    Essential Uses of Email Headers

     

    Determining a Phishing Attempt

    If you think an email is suspicious, or if they are asking for information that should be confidential, checking the email header can definitely help. It helps verify the email’s authenticity,  and gives you the capability to analyze the sender’s domain, its routing path, and authentication results. This can give you the data and information if the email is legitimate or a phishing attempt. 

    You can check the domain in the “From” field, and if the domain doesn’t match the  “Return-Path” or the SPF/DKIM checks fail, there is a large probability that it can be a phishing attempt.

    Email Delivery Issue Diagnoses

    In some cases that your email is marked as spam or did not arrive at the intended recipient, you can always check the email header. Issues like missing authentication records or misconfiguration of mail servers are most likely to cause your email to be flagged as spam. Always review the header, and it will help you identify and fix the problem.

    Improving Email Marketing Performance

    Email campaigns are one of the most effective marketing strategies. Checking and understanding email headers can help improve deliverability and marketing performance. You can analyze how emails are routed, and whether they are being flagged as spam, which can help them avoid any deliverability issues. If everything in your email headers is within the proper format then you might consider acquiring email warm-up services such as Warmy.io.

    Warmy.io: For Email Deliverability and Marketing Performance

    When it comes to email marketing, having the ideal email header is important, but in reality, what is the point of a good header if it can’t reach your intended recipient?

    Warmy.io provides free email deliverability tests that gradually and meticulously evaluate your email delivery capabilities, identify any potential problems you may have in your email settings, and offer a long list of solutions to ensure your emails are not blacklisted. 

    Its free SPF and DMARC Record Generators also simplifies the setup of your email authentication process minimizing the risk of spoofing and phishing attempts, and reducing the likelihood of encountering security-related errors. Here are some of Warmy’s benefits that ensure your email header design efforts will not go to waste.

    Email Warmups

    If you have a new or inactive email address or new domain and you send a high volume of messages, there can be a huge chance that email providers will classify your emails as spam. This can hinder the development of a positive sender reputation and the ability to connect effectively with your audience.

    Warmy’s email warmups prevent your emails from being flagged as spam by gradually increasing the volume of emails you send. Our email warmups gives you the ability to send up to 5000 emails per day which is the best option to enhance your engagement levels. 

    Domain Verification 

    Don’t let those improper email headers send you to email blacklists

    Our free email deliverability test can check your IP or domain against almost all major blacklists. You can verify up to 100 DNS testing per month,  ensuring your mail servers have a healthy setting and avoid your emails from being blacklisted. 

    This is a crucial factor for every email marketer, since there are various Internet Service Providers (ISPs) that blacklists an email server. This results in the email messages of the email server being sent directly to spam. 

    Free Template Checker

    Protocols and violations may vary depending on the email service provider. And understanding all of these at the same time can be challenging. We offer a free template checker to avoid spammy email headers, contents, or subject lines. 

    Customer Success Support and Deliverability Consultant

    Consultation from Email Deliverability Expert from Warmy.io offers personalized assistance and tailored solutions.  We provide expert advice, analysis and guidance on the best practices that guarantee an optimal email performance.

    Ensure that you have a deliverable email address, sign up for the 7-day free trial, or book a demo for profitable email marketing.

    Picture of Daniel Shnaider

    Article by

    Daniel Shnaider

    Picture of Daniel Shnaider

    Article by

    Daniel Shnaider

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