Restrict access to iframed domain through anything but its parent frame / domain

Question

I have a site on one domain (say, iframedomain.com), which is loaded via iframe through another domain (say, parentdomain.com) and I want to prevent users from accessing it directly. How do I ensure that anyone attempting to access iframedomain.com get redirected to parentdomain.com without hindering SEO to iframedomain.com?

Answer 1

Solved this issue using this script here:

http://geekswithblogs.net/rashid/archive/2007/01/13/103518.aspx