Per-User Authentication
To set up outgoing filtering for a user, make sure that the user is a valid outgoing user. This can be done in the Outgoing section of the Manage Domain interface. You can also configure outgoing user to represent an IP address and anybody from this configured IP can send mail. To add an outgoing user, click 'Users' and 'Add' in the 'Outgoing users' interface. You can also import users from CSV file or from Incoming users. See the section Users to know how to configure an outgoing user.