I have two separate web applications, one built with .NET Framework and the other built with .NET Core. Both web applications make up one solution which we ship to our customers. The solution itself is a SaaS subscription-based solution, where users would be able to sign-up with using either a Microsoft/Office 365, GSuite, or organizational account (basic username/password). We would like to restrict sign-up to organizational/business accounts only.
As I understood, Azure B2B is mainly useful when you have something internal and you would like to give external users some limited access to it. Given that I have a multi-tenant SaaS solution, I believe that Azure B2C makes more sense.
Furthermore, in our solution, we would also want the ability for external users to access Tabular Models in Azure Analysis Services and SSRS.
Is access to only organizational accounts, something that can be configured through Azure AD B2C?
Can access be granted to external users to Azure Analysis Services or other Azure tools when using Azure B2C?
You have two options
Option 1, Using Azure AD External identities solution - recommended
You can use newly released self service sign up solution in Azure AD external identities . You can very well restrict sign up to other Azure AD accounts only. However for sign up using other federation systems - you need to try on. I think as of today only Google and Facebook are supported apart from Azure AD.
Option 2, use Azure AD B2C and use app only authentication.
Azure AD B2C consumer accounts are by default not supported by Azure services or Office. But you can use app based authentication to provide these services. Your client app will call your backend api using Azure AD B2C token. Your backend app can perform all auth validations and then call the backend Azure or any other service using app only authentication mode.