To configure an e-mail client, such as Outlook, for POP3 protocol, you will need the following information:

Server Type: POP3
Incoming Server: pop.1and1.com
Outgoing Server: smtp.1and1.com

E-mail Address: Your e-mail address
User Name: Your e-mail address
Password: Your e-mail password

Note: The outgoing server needs to be authenticated with user name and password.