What is the best way to keep Authenticated user in one host around many ASP.Net web applications?

i will use data config for authentication

I will use one complete session

The best way to keep authenticated user around many asp . net application is by using sessions. 

Maintain data in database. While loading page, keep them in session variable. on logout / website close, dispose the session.

i will use sticky  session.

Windows authentication or by using single sign on (SSO) authentication

Session is good. But session variables need to be used carefully  in today's tabs based browsers. As tab uses same sessions may end up in some dirty reading writing issues.

i will use redis. it will help u also to scale your application by adding as many server u want.