Microsoft 365 External tag on new email messages

Questions

  • What does the "External" tag mean on an email message?
  • Why do some emails in my inbox show the word "External" next to the sender's name?
  • In Outlook on my phone, I see "External" instead of the sender's name — what is this?
  • Does the External tag mean a message is dangerous?
  • How do I use the External tag to spot phishing emails?

Environment

This article applies to all Bowdoin faculty, staff, and students receiving email at a bowdoin.edu address. The External tag appears in all Microsoft Outlook clients — Outlook Online, Outlook for macOS, Outlook for Windows, and Outlook for iOS/iPadOS — on messages sent from outside the bowdoin.edu domain.

Resolution

Bowdoin IT has enabled a Microsoft 365 feature that adds an External tag to any email message arriving from a sender who does not have a bowdoin.edu email address. This includes messages from colleagues at other institutions, vendors, students' personal email addresses, and other outside senders.

The External tag is a security tool. It provides a quick visual signal that the message originated outside Bowdoin, helping you identify potential spoofing attempts where an attacker uses a real-looking name but a non-Bowdoin address.

Screenshot of an Outlook email client with the "External" tag outlined in red. The tag appears to the left of the name of the sender if a message is coming from a non-Bowdoin email address.

On mobile devices, the External tag may appear in place of the sender's name or email address in the message list view.

A series of three screenshots of an iPhone using the Outlook app. The "External" tag is outlined in red. On the last iPhone image, an alert box is also highlighted.

External + familiar name = possible phishing. If a message appears to be from someone you know at Bowdoin but is tagged as External, it was sent from a non-Bowdoin address. This is a common sign of a phishing attempt. Do not click any links or open attachments — report the message using the Report Message option in Outlook. See Reporting a Phish or Spam Email in the Related Articles section.

Additional Help

If you need further assistance, you have several options:

  • Bowdoin Bot: Chat with Bowdoin Bot directly from any KB page for instant answers.
  • Phone: Call the Bowdoin College Service Desk at (207) 725-3030.
  • In person: Visit the Tech Hub in Smith Union during business hours.
  • Submit a ticket: Request assistance through the Service Catalog.
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Related Articles (2)

Microsoft 365 (M365) Email Protection
Explains the two layers of Microsoft 365 email protection at Bowdoin — Exchange Online Protection (EOP) and Microsoft Defender for Office 365. Covers how spam, phishing, malware, and suspicious links are filtered, what users will see when protection is active, and what to do if a legitimate message is blocked.
Reporting a Phish or Spam email
How to report a suspected phishing or spam email to Bowdoin IT using the Report Message option in Microsoft Outlook. Covers Outlook for macOS, Outlook Online, Outlook for Windows, and Outlook for iOS/iPadOS. No need to forward emails to IT directly.