Shibboleth SP3 and IIS10

[Costantino Grana]

Hello to everybody.

After many year of using Shibboleth 2 on Windows Server 2000 and IIS6, 
we finally decided to upgrade. Fresh install of Windows Server 2019, Add 
Roles and Features, Server Roles: Web Server (IIS), in Role Services, 
Application Development: ASP. Installed latest Shibboleth SP3 with auto 
configuration of IIS. Edited both shibboleth2.xml and attributes-map.xml 
in order to match our IdP configuration and then tried it. 
Authentication works correctly on the selected folders with HTTPS 
required, as expected.

BUT: server variables are not set! I've tried with both classic ASP and 
ASP.NET, also with the legacy enable headers, but nothing appears. Using 
Shibboleth.sso/Session, attributes are received and mapped correctly, 
but nothing is available to the applications, not even inbuilt 
attributes such as Shib-Application-ID. REMOTE_USER is correctly set to 
the eppn value.

I've tried everything I could think of, but nothing worked.

Thank you in advance for any suggestion.

Best,
Costantino Grana