I'll be adding a bounty to this, probably 200, more if you guys think its appropriate. I wont accept an answer until I can add a bounty so feel free to go ahead and answer now

Summary

Long story short, we've been tasked with gutting the authentication and authorization parts of a fairly old and bloated asp.net application that previously had all of these components written from scratch. Since our application isn't a typical one, and none of us have experience in asp.net's built in membership provider stuff, we're not sure if we should roll our own authentication and authorization again or if we should try to work within the asp.net membership provider mindset and develop our own membership provider.

Our Application

We have a fairly old asp.net application that gets installed at customer locations to service clients on a LAN. Admins create users (users do not sign up) and depending on the install, we may have the software integrated with LDAP.

Currently, the LDAP integration bulk-imports the users to our database and when they login, it authenticates against LDAP so we dont have to manage their passwords. Nothing amazing there.

Admins can assign users to 1 group and they can change the authorization of that group to manage access to various parts of the software.

Groups are maintained by Admins (web based UI) and as said earlier, granted / denied permissions to certain functionality within the application.

All this was completely written from the ground up without using any of the built in .net authorization or authentication. We literally have IsLoggedIn() methods that check for login and redirect to our login page if they aren't.

Our Rewrite

We've been tasked to integrate more tightly with LDAP, they want us to tie groups in our application to groups (or whatever types of containers that LDAP uses) in LDAP so that when a customer opt's to use our LDAP integration, they dont have to manage their users in LDAP AND in our application.

The new way, they will simply create users in LDAP, add them to Groups in LDAP and our application will see that they belong to the appropriate LDAP group and authenticate and authorize them.

In addition, we've been granted the go ahead to completely rip out the User authentication and authorization code and completely re-do it.

Our Problem

The problem is that none of us have any experience with asp.net membership provider functionality. The little bit of exposure I have to it makes me worry that it was not intended to be used for an application such as ours. Though, developing our own ASP.NET Membership Provider and Role Manager sounds like it would be a great experience and most likely the appropriate thing to do.

Basically, I'm looking for advice, should we be using the ASP.NET Membership provider & Role Management API or should we continue to roll our own? I know this decision will be influenced by our requirements so I'm going over them below

Our Requirements

Just a quick n dirty list

• Maintain the ability to have a db of users and authenticate them and give admins (only, not users) the ability to CRUD users
• Allow the site to integrate with LDAP, when this is chosen, they don't want any users stored in the DB, only the relationship between Groups as they exist in our app / db and the Groups/Containers as they exist in LDAP.
• .net 3.5 is being used (mix of asp.net webforms and asp.net mvc)
• Has to work in ASP.NET and ASP.NET MVC (shouldn't be a problem I'm guessing)
• This can't be user centric, administrators need to be the only ones that CRUD (or import via ldap) users and groups
• We have to be able to Auth via LDAP when its configured to do so

I always try to monitor my questions closely so feel free to ask for more info. Also, as a general summary of what I'm looking for in an answer is just. "You should/shouldn't use xyz, here's why".

Links regarding asp.net membership provider and role management stuff are very welcome, most of the stuff I'm finding is 5+ years old.

Edit: Added some stuff to "Our Rewrite"