1. A computer-readable medium having computer-executable instructions for implementing a method of authenticating and authorizing an extranet client to a secure intranet business application via a perimeter network, wherein connections to the secure intranet business application from the perimeter network or the extranet are not permitted, the computer-readable medium comprising: computer executable instructions for authenticating a perimeter network proxy identification of a perimeter network proxy within the secure intranet, the perimeter network proxy corresponding to an authenticated extranet client; computer executable instructions for acquiring client information associated with an intranet business application identification corresponding to the extranet client if the perimeter network proxy identification is successfully authenticated; computer executable instructions for creating an impersonation session with the intranet business application for the authenticated extranet client based on the client information associated with the intranet business application, such that the intranet business application receives request from the extranet client using the impersonation session and processes the requests as the extranet client; and computer executable instructions for transmitting information relating to the impersonation session to the perimeter network.