Customize the 404 page for ArcGIS Server Map Services

ArcGIS Server 10 internal Tomcat web root:
       \ArcGIS\Server10.0\java\manager\web_output

ArcGIS Server 10 internal Tomcat conf:
       \ArcGIS\Server10.0\java\manager\service\managerappserver\conf

You may modify the web.xml by adding the error page definition:

        ...

        <welcome-file-list>

            <welcome-file>index.html</welcome-file>

            <welcome-file>index.htm</welcome-file>

            <welcome-file>index.jsp</welcome-file>

        </welcome-file-list>

        <error-page>

            <error-code>404</error-code>

            <location>/404.htm</location>

        </error-page>

    </web-app>

And the 404 error file can put in the root (/web_output)

References for setting up app routing in IIS 7

Application Request Routing in IIS

• http://learn.iis.net/page.aspx/482/install-application-request-routing/
  
  
• http://blogs.iis.net/wonyoo/archive/2011/04/20/how-to-install-application-request-routing-arr-2-5-without-web-platform-installer-webpi.aspx
  
  
• http://blogs.iis.net/wonyoo/archive/2011/03/29/why-is-application-request-routing-version-2-5-available-only-via-web-platform-installer.aspx