How to Whitelist a Domain in Mac OS X Mail

To whitelist all email from a specific domain in the Mail app in Mac OS X  or macOS:

• Select Mail | Preferences from the menu bar in Mac OS X Mail.
• Click the Rules tab.
• Click Add Rule.
• Type a name in the Description field, such as "Whitelist: rainbowplantlife.com" to identify the new rule.
• Make sure the criteria reads If any of the following conditions are met and that the From field is followed by Ends with.
• Enter the domain name you want to whitelist in the field next to the Ends with field. Add an @ sign before the domain name to make the filter specific. For example, to whitelist all mail from the rainbowplantlife.com domain type "@rainbowplantlife.com" into the field.
• Click the plus sign next to the last condition to add another domain with the same criteria if you want to whitelist several domains.
• In the Perform the following actions section set the three fields to Move Message, to the mailbox, and Inbox or a different target folder.
• Click OK to save the rule.
• Close the Rules window.

To make sure the rule is executed before other rules that might act on the same message for other reasons, drag it near the top of the rules list. If you have a filter that color-codes certain messages based on keywords in the subject, for example, make sure the domain whitelist rule is above that labeling rule.