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ASP.NET code to detect whether IIS "Windows Authentication" is enabled

Asked 2011-06-27T16:10:14.270
11

I would like to be able to detect, from ASP.NET code, whether IIS currently has "Windows Authentication" "available"?

Starting from my application installed and currently running under "Anonymous Access", I want to detect:

  1. "Windows Authentication" component has actually been installed in IIS (e.g. some IIS7 have it not installed by default); and...
  2. "Windows Authentication" is actually "Enabled" on my virtual root/location.

I want this information to let the Administrator know whether he needs to take action in IIS before he actually attempts to switch it on on my application.

(Hence, for example, I think IIS7: How to define that windows authentication is turned on? does not help me, as that is looking at whether it is already on for my application; I want to know whether it is installed/can be turned on.)

My "solution" would need to work (or at least not "fail") with versions of IIS prior to 7 as well as 7 itself, so if there are differences there I need to know. Thanks.

asp.net iis iis-7 windows-authentication
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My answer is based on @Paul Stovell's minimum requirements (that it only needs to work for IIS 7). When WindowsAuthentication is installed, the applicationHost.config file will have the following entry in the <globalModules> section:

<add name="WindowsAuthenticationModule" image="%windir%\System32\inetsrv\authsspi.dll" />

Using Microsoft.Web.Administration.dll, which can be found in %windir%\System32\inetsrv\, one can check for the existence of the WindowsAuthenticationModule with the following code:

ConfigurationSection globalModulesConfig = config.GetSection("system.webServer/globalModules");
ConfigurationElementCollection globalModulesCollection = globalModulesConfig.GetCollection();
bool installed = globalModulesCollection.FirstOrDefault(a => a.GetAttribute("name").Value.Equals("WindowsAuthenticationModule")) != null;

Since the applicationHost.config file resides in %windir%\System32\inetsrv\config, the application making this query requires elevated privileges.

answered 2012-03-31T14:27:35.557

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