<system.applicationHost>

Article
05/14/2020

Overview

The <system.applicationHost> element contains global configuration settings that are used by the Windows Process Activation Service (WAS) in Internet Information Services (IIS) 7. This element defines many of the server-level configuration settings in the IIS 7 ApplicationHost.config file.

Of significant importance, the <system.applicationHost> element contains the configuration settings for the <applicationPools> and <sites> collections, which respectively define the collection of application pools and Web sites on an IIS 7 server.

Note

Unlike the settings that are found in <system.webServer>, settings in the <system.applicationHost> element cannot be delegated.

Compatibility

Version	Notes
IIS 10.0	The `<system.applicationHost>` element was not modified in IIS 10.0.
IIS 8.5	The `<system.applicationHost>` element was not modified in IIS 8.5.
IIS 8.0	The `<system.applicationHost>` element was not modified in IIS 8.0.
IIS 7.5	The `<serviceAutoStartProviders>` element was added in IIS 7.5.
IIS 7.0	The `<system.applicationHost>` element was introduced in IIS 7.0.
IIS 6.0	N/A

Setup

The <system.applicationHost> element is included in the default installation of IIS 7.

How To

There are no examples that are specific to the <system.applicationHost> element. For examples that configure the settings that are found within the <system.applicationHost> element, see the child elements that are listed in the configuration details section of this topic.

Configuration

The <system.applicationHost> element is defined in the ApplicationHost.config file.

Attributes

None.

Child Elements

Element	Description
`applicationPools`	Optional element. Contains default configuration settings for all application pools on the server and defines configuration settings for specific application pools.
`configHistory`	Optional element. Specifies the configuration history settings for a server.
`customMetadata`	Optional element. Contains settings that are used internally by the Admin Base Object (ABO) mapper component of IIS 7.
`listenerAdapters`	Optional element. Specifies configuration settings for listener adapters, which are components that establish communication between non-HTTP protocol listeners and WAS.
`log`	Optional element. Specifies the logging mode for a server.
`serviceAutoStartProviders`	Optional element. Specifies a collection of managed assemblies that will be loaded when the `AlwaysRunning` is specifed for an applocation pool's startMode. Note: This element was added in IIS 7.5.
`sites`	Optional element. Defines all sites on the server, and all applications and virtual directories in those sites.
`webLimits`	Optional element. Configures TCP/IP connection and bandwidth limits.

Configuration Sample

The following configuration sample defines a simple, static-content-only <system.applicationHost> element, with a single application pool ("DefaultAppPool") and a single Web site ("Default Web Site").

<system.applicationHost>
   <applicationPools>
      <add name="DefaultAppPool" />
     <applicationPoolDefaults>
         <processModel identityType="NetworkService" />
      </applicationPoolDefaults>
   </applicationPools>
   <customMetadata />
   <listenerAdapters>
      <add name="http" />
   </listenerAdapters>
   <log>
      <centralBinaryLogFile enabled="true" directory="%SystemDrive%\inetpub\logs\LogFiles" />
      <centralW3CLogFile enabled="true" directory="%SystemDrive%\inetpub\logs\LogFiles" />
   </log>
   <sites>
      <site name="Default Web Site" id="1">
         <application path="/">
            <virtualDirectory path="/" physicalPath="%SystemDrive%\inetpub\wwwroot" />
         </application>
         <bindings>
            <binding protocol="http" bindingInformation="*:80:" />
         </bindings>
      </site>
      <siteDefaults>
         <logFile logFormat="W3C" directory="%SystemDrive%\inetpub\logs\LogFiles" />
         <traceFailedRequestsLogging directory="%SystemDrive%\inetpub\logs\FailedReqLogFiles" />
      </siteDefaults>
      <applicationDefaults applicationPool="DefaultAppPool" />
      <virtualDirectoryDefaults allowSubDirConfig="true" />
   </sites>
   <webLimits />
</system.applicationHost>

Sample Code

There are no code samples that are specific to the <system.applicationHost> element. For code samples that configure the settings that are found within the <system.applicationHost> element, see the child elements that are listed in the configuration details section of this topic.

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