title: How to check if two users of web application belongs to same netowork/LAN/domain
body: <p>I have a web application with security concerns that the user should be able to login from his office network only. even if he carries his laptop outside his office he should not be able to login into an application.Also the access to application will be granted by admin user and for this the condition is the user should be under same netowork/LAN/domain as admin user.</p>
  
  <p>The problem is how can I identity the user and admin are in both same network.is there any framework which can do browser communication on two different PCs in LAN or same network ? is there any way I can find network identifier of user?</p>