Allow only one concurrent login per user in ASP.NET

Question

Is it possible to allow only one concurrent login per user in ASP.NET web application?

I am working on a web application in which I want to make sure that the websi

Answer 1

The login credentials are stored on the cookie, so to know if the user is logged in you need to keep this informations on server, prefered on a database because the database can be the only common place among web garden or web farm.

What you can keep, is on a table, that the user A is logged in or not, flag it that is logged out, maybe last user interaction to have a timeout, etc...

So let say that the User A, is logged in, then you open a flag on the database for that user, that is now logged in, and if is try to logged again, you keep him out. To make this work you need to either say to your users to log out, or to keep a time out, similar to the time out of the credentials.