I am having WAMP (Windows, Apache, MySQL and PHP) on a web server. The box is available within our organization network only. I need to implement SSO (Single Sign On) for a tool to be launched for people of our organization only. The tool should be able to detect which intranet user is visiting our site automatically instead of promptly asking organization n/w username / password. I am not sure how to implement that both at Apache and back end code side - such that a PHP script should be able to detect the 'USER' at least. Note if I can avail the 'USRE' I can do LDAP validation to authenticate this user. I googled but nothing is given as constructive that would work 100%. Can anyone please guide me with some basics?