Joomla Login-only homepage.

I am working on a Joomla 1.7 website intended for private use. Therefore i require a homepage which consists of a login screen only. The rest of the site may only be accessable after a valid login. Registrations will be private and done by the website owner. As long as there is no valid login the only URL visible should be the site itself either by name or IP When a visitor attemps to enter one of the site's URL's manually without logging in first he should be re-directed to the login homepage. I.e. no access to anything without passing through that homepage login. With your bid you MUST explain HOW you intend to achieve this. I have a preference to stay as close to the Joomla standard as possible however i'm open to alternatives. Be clear if you suggest a solution within the Joomla framework or something outside Joomla that wraps the whole site.