In Office 365, you’ll use their “Connection Filter” options:
- Sign into Office 365 and click “Admin” > “Admin Centers” > “Exchange“
- Under the “Protection” list, choose “Connection Filter“
- Click the “Pencil Icon” to edit
- Choose “Connection Filtering” on the left side menu
- Click the plus “+” symbol and add the first IP and click “OK“(find our current IP addresses for whitelisting here.)
- Repeat Step 5 to add our second IP address.
- Check the “Enable Safe List” checkbox, if necessary
- Hit Save
