Understanding the “External” Tag in Outlook/Office 365: A Guide for Customers


In today’s digital landscape, email communication plays a pivotal role in our personal and professional lives. With the constant flow of messages, it’s essential to stay vigilant and be aware of potential risks associated with external emails. In Outlook/Office 365, one helpful feature is the “External” tag, designed to assist users in identifying emails originating from outside their organization. In this blog post, we’ll delve into the purpose of the “External” tag and provide guidance on how to approach these emails securely.

1. Purpose of the “External” Tag

The “External” tag serves as a visual indicator within Outlook/Office 365, alerting users to emails that originate from external sources. Its primary purpose is to differentiate between emails sent from within an organization and those from external senders. By displaying this tag prominently, it raises awareness and prompts users to exercise caution when interacting with these messages.

2. Email Classification

It’s important to note that the “External” tag does not automatically classify an email as malicious or unwanted. Instead, it is a helpful reminder for users to evaluate the content, context, and sender before taking any actions. While external emails may require additional scrutiny due to their unfamiliar origin, it’s essential not to make assumptions solely based on this tag.

3. Identifying Potential Risks

Although the “External” tag provides a useful visual cue, it does not guarantee the legitimacy or security of an email. Cybercriminals can employ sophisticated techniques to bypass security measures and send malicious emails that appear as if they are from external sources. Therefore, users should remain vigilant and employ best practices when dealing with any email, regardless of the “External” tag.

4. Importance of User Judgment

Evaluating the credibility and legitimacy of an email rests primarily on the user’s judgment. While the “External” tag acts as an alert, users should employ critical thinking and consider several factors, including the sender’s reputation, email content, and any suspicious or unusual elements. Trusting one’s instincts and following best practices for email security is crucial.

5. Reporting Suspicious Emails

To combat potential threats effectively, users must report any suspicious or potentially malicious emails, even if they carry the “External” tag. Reporting such emails to the organization’s IT or security team enables prompt investigation and action. This collaborative effort is vital in maintaining a robust email security framework and protecting the organization as a whole.

6. Additional Security Measures

While the “External” tag provides a valuable visual indicator, it should be viewed as one layer of defense within a comprehensive email security strategy. Organizations should implement additional security measures, such as robust spam filters, antivirus software, and ongoing employee training. By combining these measures, organizations can mitigate risks associated with external emails effectively.


In the realm of email communication, the “External” tag in Outlook/Office 365 serves as a valuable tool for users to identify emails originating from outside their organization. However, it’s important to understand that the tag alone does not determine the legitimacy or security of an email. Users must exercise caution, rely on their judgment, and employ best practices when interacting with any email, regardless of the “External” tag. By fostering a culture of email security and collaboration, organizations can enhance their defenses and mitigate the risks associated with external emails.

Remember, the specific recommendations and practices mentioned in this blog post should be tailored to your organization’s policies and security framework. Consult with your IT or security team to ensure accurate information and the most effective approach for your specific MSP.