PHP retrieve remote domain

Is there a way to find the domain name that the remote computer is connected to? This is for an authentication setup to allow access for a specific network. I have tried exec(“ipconfig 2&>1”, $output) and shell_exec(“ipconfig /all”) but it doesn’t give me what I need for 2 reasons: 1. it doesn’t have all the information, including the domain name 2. it retrieves the information from the server, not the remote computer.

Any suggestions?

Thanks
Troy