setting up one membership for a few asp.net website

In sharing hosting provider I have a website and a few sub-domain which each one is a separate asp.net web-app with separate Database (SQL Server 2005) .

At the moment I use default ASP.NET Membership Provider for Users and Roles . I would like When a user register in one web-site , she could log-in to other we开发者_开发问答bsites too .( I mean doesn't force users to register in all websites ) How could i do that ?

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Ensure you have the same data connection and applicationName defined for the membership and role manager providers in each application.

The data connection attribute defined what database (obviously), and the application attribute then partitions the data within the database: if these are the same then the web apps are using the same information.