852 Chapter 17 • Troubleshooting 101: Diagnostics in IIS 7.0 Confi guring Custom Error Messages Using IIS Manager Let’s fi rst take a look at viewing and updating the Custom Errors pages using IIS Manager. After opening and connecting to an IIS 7 server, click the Error Pages icon in the IIS section and then click Open Feature from the Actions pane (or simply double-click the Error Pages icon), as shown in Figure 17.3. These are the default Error Pages defi ned for the entire Web server. Any changes done at this level will impact the error pages settings for all the sites supported on that IIS 7 server, except where a site or application overrides those values. There are a number of options available at this point from a Status Code perspective. You can add a Status Code by clicking Add. . .in the Actions pane (see Figure 17.4). The Add Custom Error Page dialog box will allow you to provide a Status Code (e.g., 404) or a Substatus Code (e.g., 404.14). The Path Type fi eld allows you to defi ne the kind of action to take based on the value in the path (see Figure 17.4). Table 17.1 provides details on the available path types. Figure 17.2 IIS 7.0 Detailed HTTP Error Message Troubleshooting 101: Diagnostics in IIS 7.0 • Chapter 17 853 Figure 17.3 The IIS Manager Figure 17.4 The Add Custom Error Page 854 Chapter 17 • Troubleshooting 101: Diagnostics in IIS 7.0 Controlling the custom errors can be done at a variety of locations within IIS 7, and thus it’s important to understand where these settings are actually being stored. For the entire Web server, those changes are done in the applicationHost.confi g fi le, which is located in the \Windows \System32\Inetsrv\Confi g folder. Additionally, when you’re managing a given Web site, those changes can also be stored in the applicationHost.confi g fi le, or they can be managed within the web.confi g for the site. HTTP error responses can be defi ned for the following IIS levels: ■ Web server ■ Web site ■ Web application ■ Physical directory ■ Virtual directory ■ File (URL) These settings were previously available in IIS 6.0 but were not widely known and utilized. In IIS 6.0, this was done by setting a number of properties (HTTPErrorCode, HTTPErrorSubcode, URL, HandlerURL, FILE, or Filename) and using the proper combination, depending on the type of redirection you where going to use. With IIS 7.0, this is much easier to implement in the User Interface and via XML confi guration. <httpErrors> Confi guration With the rich integration between ASP.NET and IIS 7.0, a developer or administrator can defi ne the httpError confi guration at the server, Web site, or virtual directory level. This provides a greater amount of control versus what was previously available in IIS. The default <httpErrors> section is defi ned in the applicationHost.confi g fi le. (More information on the location and use of the applicationHost.confi g fi le can be found in Chapter 15). Table 17.1 Available Path Types Path Type Description Path Examples File Points to a static fi le 404.htm Execute URL Points to a dynamic fi le Error.aspx Redirect Redirects the client browser to a different URL http://<URL> Troubleshooting 101: Diagnostics in IIS 7.0 • Chapter 17 855 <httpErrors> <error statusCode=“401” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“401.htm” /> <error statusCode=“403” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“403.htm” /> <error statusCode=“404” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“404.htm” /> <error statusCode=“405” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“405.htm” /> <error statusCode=“406” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“406.htm” /> <error statusCode=“412” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“412.htm” /> <error statusCode=“500” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“500.htm” /> <error statusCode=“501” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“501.htm” /> <error statusCode=“502” prefi xLanguageFilePath=“%SystemDrive%\inetpub\custerr” path=“502.htm” /> </httpErrors> The default location for the custom error pages is %SystemDrive%\inetpub\custerr. Within that folder will be additional folders that map to a localized code. For U.S. English, that subfolder is labeled “en-US.” The localized version that will be used for the response will be defi ned by the actual browser setting that is set by the end user. Table 17.2 Child <error> Node Attributes and Values Attribute Name Value defaultPath Default path to the HTTP error fi le or URL that will be used within the child <error> node. detailedMoreInformationLink At the bottom of a Detailed error page, a “More Information” link redirects the user to a Microsoft Support article. Setting the DetailedMoreInformationLink property can override the base URL for this link. This can be extremely useful if you want to capture these errors, even for internal testing, to store in a database or provide a response using an internal Knowledge Base article that directly references a particular product or module (Default=“http://go.microsoft.com/fwlink/ ?LinkID=62293”). defaultResponseMode Used to defi ne the default Response Mode that will be used within the child <error> node (Default=File): File Static fi le will be used. Continued 856 Chapter 17 • Troubleshooting 101: Diagnostics in IIS 7.0 Table 17.2 Continued Attribute Name Value ExecuteURL Points to a URL within the same server. For this to work, it must be a URL that points to a dynamic page (e.g., ASPX page) that resides within the same application pool that generated the error. Needless to say, you might not want to set this at the server level if you host a number of sites with more than one application pool. By default, you will receive an error if you attempt to do this to a location outside the appPool. However, you can actually get around this and allow it to happen with an appropriate registry key. Read the “Some Independent Advice” sidebar for more details. Redirect Redirects to a specifi c URL. The URL can be on the same server or a completely different server or site. errorMode Defi nes whether a Custom Error page or Detailed Error page is used upon a given error being generated (Default=DetailedLocalOnly). DetailedLocalOnly A detailed error will only be displayed when the request comes from the local machine. Custom Custom pages will be used upon an error. Detailed A detailed error response will be provided regardless of a custom page being assigned or outside the local machine. existingResponse ASP.NET and IIS 7 are not integrated when it comes to error responses. Thus this value allows you to control the way you want to handle error responses (Default=Auto): Auto IIS 7.0 will go through a series of checks to decide which error response will be used: 1. If the IHttpResponse::SetStatus method was called with the fTrySkipCustomErrors fl ag, the existing response is passed through, and no detailed or custom error is shown. 2. If the ErrorMode property is set to Custom, the response is replaced. 3. If ErrorMode is set to Detailed and there is an existing response, the response is passed through. 4. If ErrorMode is set to Detailed and there is no existing response, the response is replaced with a detailed error message. . take a look at viewing and updating the Custom Errors pages using IIS Manager. After opening and connecting to an IIS 7 server, click the Error Pages icon in the IIS section and then click Open. were not widely known and utilized. In IIS 6.0, this was done by setting a number of properties (HTTPErrorCode, HTTPErrorSubcode, URL, HandlerURL, FILE, or Filename) and using the proper combination,. 7.0 Controlling the custom errors can be done at a variety of locations within IIS 7, and thus it’s important to understand where these settings are actually being stored. For the entire Web server,