asp.net mvc - MVC4 Simple Membership authentication with multiple databases or providers -

i'm working on mvc4 site using simplemembership handle user accounts , role based authentication. have site , we'd implement single sign on system allowing users existing site log in 1 building. best way achieve , leverage existing roles based authorization i'm using on mvc4 site. possible have multiple membership providers (i.e. use built in 1 , if user not found, attempt authenticate via custom provider i'll write (once work out how!). or better abandon built in membership/roles , roll own?

i thought of letting websecurity check local database , if user not found, query 2nd database , if users credentials valid, create local account them. 1 issue approach if user called fred registers on mvc site, , user other site called fred logs in, couldn't create them local account same username. prefix/suffix username text indicate other site lose single sign on feature.

we want integrate ad authentication staff in future.

so i'm looking best way authenticate users multiple databases , keep using roles based authentication?

i've done little digging wondering if adfs might useful this.

any or advice appreciated!

i recommend use of identity server handle login request , switching claim based authentication instead of role based authentication if can.

i went thinktecture identityserver

pluralsight.com have course on it.

thinktecture identityserver build on top of simple membership , supports multiple protocol such

1. ws-federation
2. ws-trust
3. openid connect
4. oauth2
5. adfs integration
6. simple http

i recommend checking

good luck