Skip to main content

Email: Spam Filtering and Junk Mail

Short version: Check your junk mail folder from time to time.

This article applies to: Email for Faculty and Staff


Spam makes up more than two-thirds of all email traffic. Every email in the world passes through a gauntlet of junk mail / spam filters designed to protect recipients from all that spam.

With so much complexity, it’s inevitable that the occasional message will be misjudged. Take these two steps to make sure you aren't inadvertently missing important messages, or being unnecessarily bothered by spam.

1) Check your junk mail folder regularly for legitimate messages.

  • Cmail: look at the "Spam" label.
  • Outlook, Outlook on the Web, or Apple Mail: look in the "Junk E-mail" folder.

2) If you're getting too much spam, or messages are getting marked as spam when they shouldn't, check the junk mail settings for every method you use to check your messages, including your phone. When messages are being mysteriously moved or "missing," it's often because different junk mail settings or rules are being applied by different email clients.

Cmail (student email)

Office 365 (faculty/staff email)

The Automatic Junk Filtering and Rules created in Outlook on the Web are applied on the server, so they will be applied no matter which email client you use to read your messages. Having all your settings in one place (Outlook on the Web) makes it easier to diagnose if something behaves oddly.

What Protects your Cornell Email from Junk Mail / Spam

Your Cornell email is protected from junk mail / spam by two (or more) layers:

  • By Google or Microsoft:
    Spam defenses used by Google (for Cmail student email) and Microsoft (for Office 365 faculty/staff email) in their worldwide email systems
  • In the entire Cornell email system:
    A university-tuned tool called PureMessage, which scans all messages in the Cornell email system for viruses and for spam-like characteristics (details on what PureMessage does).
  • In your email account on Cmail or Office 365:
    Personal junk mail settings and rules you can choose to apply to your mailbox. These are stored by Google or Microsoft.
  • In your email client (Outlook, an app on your phone, Apple Mail, etc.):
    Personal junk mail settings and rules you can choose to set for a particular email client. These are stored by the email client, and are only applied when you use that email client to check for messages.

Depending on what systems your messages pass through (if, for example, you have messages sent to one address forwarded to another), there may be additional layers of protection.

Was this page helpful?

Your feedback helps improve the site.

Comments?