I have multiple web sites in IIS 7.0 all running on port 80 responding to different http headers. All the sites use Digest Authentication. Whenever a user changes sites (site1.mycompany.com -> site2.mycompany.com) they have to re-authenticate. How can i allow them to log in once, using digest authentication, and never have to log in again during that Internet Explorer session? Implimenting a forms-based authentication solution is NOT a viable option.