Need help about IP Addresses

Hi!

I want to know the real IP address of the client accessing my app.  Why?
So I can compare it with my IP address.
I'm working on a web based desk top app and I do not want an employees logging in from anywhere other than physically in my office; unless an admin.

None of these below returns anything useful from behind LOCALHOST, it returns my own IP address as ::1 
Will I get a better result on a public host?  Is there a PHP.ini setting that I need to make?
Perhaps you have a better approach....

PHP Code:

if(!empty($_SERVER['HTTP_CLIENT_IP'])){
   //ip from share internet
    $ip = $_SERVER['HTTP_CLIENT_IP'];
}
elseif(!empty($_SERVER['HTTP_X_FORWARDED_FOR'])){
   //ip pass from proxy
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
}
else{
    $ip = $_SERVER['REMOTE_ADDR'];
} 


Thank for help