Step 1
Log in to the Webmail Portal.

Webmail portal

Step 2

Click the Configuration icon toward the top-right of the page and select Edit Settings.

1&1 WebMail start page

Step 3

In the Configuration menu, select Anti-SPAM from the Mail section and then click Show beneath the Whitelist option.

Edit Settings

Step 4

Click the Add button.

Mail menu

Step 5

Type in the e-mail addresses or the address range in the provided textbox. The address range will allow you to filter any e-mail address containing a specific domain name as seen in the image below. When finished, click on the Add button to finalize the procedure.

Whitelist menu

Step 6

The newly whitelisted address will automatically be saved.
Mail menu