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

You could add a flag column in the user table that indicates that a user is currently logged in.

When a users attempts to log in you check the flag if it's true (that users account is already currently used) then you don't allow the new user to log in, if the flag is false the users is allowed to log in as there account is not being used by anyone else at this time.

Be aware though that unless the uses actively logs out, you cannot know when the users moves on to something else (goes to different website or closes the browser, etc.) so you need to set some kind of session timeout that will automatically log out the user if there are no new requests within a specified time period.

This means that if a users closes his/her browser and try to log in on a mobile device for example, he/she will be unable to log in until your specified session timeout runs out, so give the timeout a bit of thought as you don't want the user to get logged out to quickly (if he/she is reading a long page, etc.) and you don't want the users to be unable to log in on another device for hours if he/she forgot to log out before leaving the home.