Security issue

Hi, I'm making a PHP webpage, and would like to be able from where this page is called, in order to reduce the possible number of callers to a predefined list. Thus, I've had a look into getenv(HTTP_REFERER). The problem is that if somebody is using the same name or ip in its own local network, then he can connect by redirecting his request to my page. The big question is so: is there a possibility to allow only connection between pages located in the same LAN? but be careful, this pages will also be read over the internet. What i want to avoid is the call of my 'protected'web pages from 'untrusted'pages... Thanks ... Geraud ____________________________________________________________________ Géraud P. Krawezik www.chez.com/krawezge ENSIETA Graduate www.ensieta.fr PhD Student www.lri.fr Artabel Engineer www.artabel.net +33(0)1 69 18 95 86