I also want to do a similar thing like you people are trying here.
I want to implement " concurrent floating license locked to MAC address"
The user has a LAN with one PC designated as 'server'.The SQL database will sit on this server.Our application can be installed on any number of client machines which are part of the LAN.
Say we have 25 floating licenses, so at a time 25 clients can use the app.
When the client opens the app, an activation key will be entered by user and along with this the mac id is sent to license server. After the validation, a text file containing unique hash code will be sent to the client.
On the server side, we should maintain a SQL database for managing licenses.
The license count should be incremented and decremented as and when the client lauches the APP.