Let say you want to allow chat only your site users, how can you do that?

1. You will need LHC since 2.04 version
2. Also this extension https://github.com/LiveHelperChat/livehelperchat-extensions/tree/master/verifyuser
3. Now just download this extension and put it in extension folder, so it should look like
   1. extension/verifyuser/...
4. Activate this extension in settings.ini.php file
   1. 'extensions' => array('verifyuser')
5. Now you can just edit verifyuser/bootstrap/bootstrap.php file there will be defined callback which get's all the chat data. https://github.com/LiveHelperChat/livehelperchat-extensions/blob/master/verifyuser/bootstrap/bootstrap.php#L21
6. Also instead of of pure DB check you can use curl or whatever you want.