Context:
I have an ASP.NET WebForms Website (not a Web Application) that I'm reimplementing in a new ASP.NET MVC Web Application with a new CMS. These sites will have the same second-level domain, but different host names (e.g. site1.site.com and site2.site.com).
The WebForms site is quite large, so I'll be migrating parts of the WebForms site over to the MVC site over a long period of time. Once all of content of the WebForms site has been moved over to the MVC site, the WebForms site will be retired, and both host names will point to the MVC site.
Problem:
The WebForms site uses Basic Authentication and the MVC site uses Forms Authentication. Both talk to the same authentication service on the backend, and take the same credentials from the user.
I don't want users to have to sign in to these sites separately; they should only see one sign in prompt. This appears to be possible if both sites use Forms Authentication, but is it possible to set this up when one site uses Forms Authentication and the other uses Basic Authentication?
Specifically, is it possible for a user to sign in to the site using Forms Authentication and be authenticated on the Basic Authentication site, and vice versa?
