Login in same user at the same time in different machine

[Mathews P Srampikal]

How to restrict the a user (userid) to restrict to login in different machine,if he is already logged in.
For example...i have already logged in using my id say admin.this admin sould not be able to login again if he is already logged in.suggestions will be better without using database checking.
Thanks,

[Bhushan Jawle]

If u don't want to do that in DB, you will need to have the info. somewhere. ServletContext seems like a good candidate. Do make sure that you synchronize ur access to this structure

[sampy jagan]

Track the IP address of the User.