Triggering SP error page / restrict access to a list of users

[Manuel Haim]

Hi list,

can anyone tell me if it is possible to trigger an SP error page from
within the protected web application?

We have a use case where, after login, the web application should check
a local database for allowed users, and then trigger the SP's "access
denied" page if the user is not permitted to access the application.

Would generating an xml file for SP XML Access Control [1] be an
alternative for us? How is its performance? Or should this scenario be
typically handled by setting an "eduPersonEntitlement" within our LDAP
directory?

-Manuel

[1] SP XML Access Control
https://wiki.shibboleth.net/confluence/display/SHIB2/NativeSPXMLAccessControl