Multiple logons by single user

Hi all,

 

 

Is there any way of restricting a user to only be able to have one current logon sessions at a time.

 

 

I have been able to logon on from one host and then logon as the same user from another host.

 

 

Am unable to find where you can restrict the number of current user sessions, or to stop a user logging on if they already logged in on another host.

 

 

Any points, hints, ideas or a solution would be gratefully appreciated.

 

 

Thanks

 

Keith