HTTP_REFERER and Access Control

[Philippe Marcoussis <philippe.marcoussis@xxxxxxxxx>]

Hello,

I am facing a problem, and i don't known how to solve it.

I have two web sites working and available on the internet :

- applications.example.com

- secure.example.com

I would like :

1) to allow FULL access FROM applications.example.com TO secure.example.com  ( without any authentication)

AND

2)  to allow access FROM Internet TO secure.example.com only with LDAP Authentification.

PS: I know how to configure ldap authentication, that is not the matter

What apache directive should I use ? mod_rewrite ? http_referer ?

Thanks,