ASP.NET-MVC How to return the correct response code?

Question

Let's look at a simple example:

Route configuration

public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( name: "Test", url: "{action}", defaults: new { controller = "Api" } ); } 

controller

 public class ApiController : Controller { public ActionResult Test() { return Content("Test"); } } 

If we call it the following URL: www.mysite.com/test we get the expected result, namely the line "Test".

But if we try to access some existing http endpoint, for example

 www.mysite.com/noneexisting 

We get a 500 server response, indicating an internal server error. This URL should lead to a 404 response code indicating a non-existent resource. This is so wrong. This is misleading for the consumer api. Why is this so? How to configure IIS, MVC to return the correct response codes?

Full server response:

HTTP / 1.1 500 Internal server error Content-Type: text / html Server: Microsoft-IIS / 8.0 Date: Wed, 03 Jun 2015 12:38:39 GMT Content-Length: 75

The page cannot be displayed because an internal server error has occurred.

For more information, I include my web.config. This is almost a stock, as VS did.

 <?xml version="1.0" encoding="utf-8"?> <!-- For more information on how to configure your ASP.NET application, please visit http://go.microsoft.com/fwlink/?LinkId=152368 --> <configuration> <configSections> <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --> <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.4.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /> </configSections> <appSettings> <add key="webpages:Version" value="2.0.0.0" /> <add key="webpages:Enabled" value="false" /> <add key="PreserveLoginUrl" value="true" /> <add key="ClientValidationEnabled" value="true" /> <add key="UnobtrusiveJavaScriptEnabled" value="true" /> </appSettings> <system.web> <compilation targetFramework="4.0" /> <authentication mode="Forms"> <!-- no authentication at all --> </authentication> <authorization> <allow users="*"/> <!-- this will allow access to everyone to register.aspx --> </authorization> <pages> <namespaces> <add namespace="System.Web.Helpers" /> <add namespace="System.Web.Mvc" /> <add namespace="System.Web.Mvc.Ajax" /> <add namespace="System.Web.Mvc.Html" /> <add namespace="System.Web.Optimization" /> <add namespace="System.Web.Routing" /> <add namespace="System.Web.WebPages" /> </namespaces> </pages> <profile defaultProvider="DefaultProfileProvider"> <providers> <add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </profile> <membership defaultProvider="DefaultMembershipProvider"> <providers> <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" /> </providers> </membership> <roleManager defaultProvider="DefaultRoleProvider"> <providers> <add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </roleManager> <!-- If you are deploying to a cloud environment that has multiple web server instances, you should change session state mode from "InProc" to "Custom". In addition, change the connection string named "DefaultConnection" to connect to an instance of SQL Server (including SQL Azure and SQL Compact) instead of to SQL Server Express. --> <sessionState mode="InProc" customProvider="DefaultSessionProvider"> <providers> <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" /> </providers> </sessionState> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false" /> <modules runAllManagedModulesForAllRequests="true" /> <handlers> <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" /> <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" /> <remove name="ExtensionlessUrlHandler-Integrated-4.0" /> <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" /> <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" /> <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" /> </handlers> <staticContent> <!-- font files --> <remove fileExtension=".eot"/> <mimeMap fileExtension=".eot" mimeType="application/vnd.ms-fontobject" /> <mimeMap fileExtension=".otf" mimeType="font/otf" /> <mimeMap fileExtension=".woff" mimeType="font/x-woff" /> <mimeMap fileExtension=".svg" mimeType="font/svg" /> </staticContent> </system.webServer> <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <dependentAssembly> <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" /> <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" /> </dependentAssembly> <dependentAssembly> <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" /> <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0" /> </dependentAssembly> <dependentAssembly> <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" /> <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" /> </dependentAssembly> <dependentAssembly> <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" /> <bindingRedirect oldVersion="0.0.0.0-4.5.0.0" newVersion="4.5.0.0" /> </dependentAssembly> <dependentAssembly> <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral" /> <bindingRedirect oldVersion="0.0.0.0-1.6.5135.21930" newVersion="1.6.5135.21930" /> </dependentAssembly> </assemblyBinding> </runtime> <entityFramework> <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" /> </entityFramework> </configuration>