Documentation
Configuration / ExternalAuthenticator.external_auth_url
This option enables you to specify a URL to a external authentication page this page can be located on a remote server or be written in another language than PHP. So it makes it possible to install and use the software on a ASP or JSP site and authenticate against that sites sessions.
$moxieManagerConfig['ExternalAuthenticator.external_auth_url'] = "auth_example.jsp";
<add key="ExternalAuthenticator.external_auth_url" value="auth_example.asp";
Check the ExternalAuthenticator folder in your install for examples for many languages.