htaccess request forwarding if internal ip

Question

Is there a possible htaccess directive that can transparently forward request from index.php to index_internal.php if the request is coming from an internal ip range?

Answer 1

ok here's my code (no redirect) based on wikipedia's private network list

RewriteEngine on
RewriteCond %{REMOTE_ADDR} ^10\. [OR]
RewriteCond %{REMOTE_ADDR} ^172\.[1-3]{1}\d{1}\. [OR]
RewriteCond %{REMOTE_ADDR} ^192\.168\.
RewriteRule ^index\.php index_internal.php [NC,QSA,L]