Hi

I have a client who wants to stop multiple logins for example being able to log in as the same user on two or more pc's is there a way to resolve this issue ?

Thanks

So it is not possible ? , though it stops more than one person gaining access to the site , this could cause a security issue.

But how come thousands of websites can?

simply someone logs into the site as John then someone else trys to log into the same account on another machine and the site wont let them in because someone else is already logged into that account ?