Help with login system

[yesorno]

I need to create a log in system in LAN. The central server is supposed to the admin. As soon as the user logs into any system in the LAN the server should "know" it and the entry should be made into database(mysql). Similarly when the user logs out. I want to make this system using Java. Please i need your suggestions what are the possibilities in which this can be created

[yesorno]

7 views and no reply ?

[Old Pedant]

This it the part that I can't see any way to do:
As soon as the user logs into any system in the LAN
Okay, so the user logs into, say, MySQL. How will your Java code ever "see" a login to something that it has absolutely no knowledge of or access to?????

[yesorno]

Hmm..let me explain...

I thought of two login ways...

1) create a GUI where the user enters username and password and sends it to server using a button. All this is in LAN.
2) Just switch on the computer and information ( might be host name) goes to the server as it is connected in LAN.

I don't want it to work in the first method. Can there be some method where the log in information is known by the server without opening GUI( to tell it in raw form)

[Old Pedant]

But you are making the assumption that some central system *can* be aware of people logging into to any application or service on the system. I don't think that is true. You could maybe find any user who *connects* to the system--espeically on linux where you could create a custom version of the operating system to notify you of such connections if there was nothing already available--but that's not the same thing as "logging in". A login is controlled by each application separately from the operating system, assuming that a given application exposes itself to the network.

Now, you can detect logged in *users* in most every operating system. But that means logged into the operating system, not just to some application via some socket/port.