Blocking login on the same username from diffrent computers

[<YaronKh@xxxxxxxxxxxxx>]

Hello

 

I'm looking for away to block login to my web site from different computers on the same username,

In other word: 

Only one person can be logged on to the web site with a username, 

if anyone else tries to log on while the first person is still logged on he will be blocked until the first person singed out.

 

Thanks

Yaron