IIS7: Why is the isAnonymous property of the NT Authority\IUSR identity false?

In IIS 7 with an application configured for impersonation, I am seeing that the anonymous user identity is NT Authority\IUSR and has properties isAuthenticated=true and isAnonymous=false. Shouldn't开发者_StackOverflow中文版 the isAnonymous property be true? I can check for the anonymous user by name but who knows, they may change it again in IIS 8.

Setting IdentityImpersonation to true in IIS7 you have two options:

1. run as a user authenticated by IIS7 or run as an arbitrary user that you set up (here isAnonymous=false).

2.using Anonymous authentication and chose to run the ASP.NET application as the authenticated user, the application would run under an account set up for anonymous users (typically, IUSR).

http://technet.microsoft.com/en-us/library/cc730708(WS.10).aspx