See our Rules (Filters) in Outlook on the web article for a general description of rules. This article focuses on the best way to filter e-list messages. 

Before defining your rule(s), you need to set up the folder(s) where your messages will be placed. See our Folders in Outlook on the web article for more information.

1. In Outlook on the web, on the red, Cornell-themed toolbar, click the gear icon.
2. At the bottom of the Settings panel that opens, click View all Outlook settings.
3. In the left column, click Mail.
4. In the second column, click Rules.
5. Click Add new rule.
6. Give your rule a descriptive Name.
7. In the Add a condition dropdown list, under Keywords, select Message header includes.
8. In the text field that appears next to your selection, enter the following:
   List-Id: <listname-l.cornell.edu>
   replacing listname-l with the name of your list.
   For example: List-Id: <limnology-l.cornell.edu>
   Note that even though this looks like an email address, there's a period instead of the @ symbol.
9. Use the Add an action dropdown list to select what you want to happen. This is typically Move to or Categorize, but this is up to you.
10. Depending on what action you select, you’ll then indicate the folder, category, or person associated with the action you selected.
11. When finished, click Save at the top of the new rule panel.
12. To return to your mailbox, close the Settings window.

You need separate rules for each list. If you try to “Add another condition” to indicate a second list for this rule, the rule will only apply if the message was sent to both lists, which it probably was not.