To make a connection to MySQL you need the following information from Control Panel:
MySQL Host Name
You can follow the steps below to find this information.
Log in to the 1&1 Control Panel using your Customer ID OR domain name and your password.
If you have only one package, you will land on the Administration page. If you have more than one package, select the package in question to reach its Administration page.
Click the MySQL Administration link from the Web Space panel.
Optional: Click the Edit button for the database which needs its password reset.
Click the Edit button
Optional: On this next page, you will be prompted to enter a new password into two text boxes to verify spelling of the password. You may optionally create or change the database's description such as "joomla database" for your own reference. When you have completed filling out the necessary fields, click the Save button to update the changes.
Set a new password and click Save
For additional information, you may want to reference: