Webmail provides a tool that allows you to block or allow email from specific senders. You can add up to 1000 entries in the Blocked Senders list and 1000 entries in the Allowed Senders list.
Make sure that you enter the sender’s email address or domain as it appears in the sender’s “Return-Path.” The return path is in the first line of the email headers. This may not be the same as the address that is displayed in the From field of the message.
Note: If you see the following error message when trying to add an address to your Blocked or Allowed list, you have reached the maximum address limit.
If this happens, you should consider revising your Allowed Senders and Blocked Senders lists to fit within the limit. Replacing multiple addresses that are in the same domain with a wildcard (*) is one way to trim down these lists.
If you want to add a domain to the Allowed or Blocked Senders list, the domain name must be preceded by *@ (for example, *@example.com).
Important: Be careful when adding entire domains to your list. If you add something like *@hotmail.com to your Blocked Senders list, you are blocking every single sender with a Hotmail address.