Which of the following files will you use to identify system specific information to reduce future
compilation changes to the application?
Each correct answer represents a complete solution. Choose all that apply.

A.
Web.config

B.
Trace.axd

C.
Global.asax

D.
Machine.config

Explanation:
The Web.config and Machine.config files will be used to identify system specific information to
reduce future compilation changes to the application. Web.config is the main settings and
configuration file for an ASP.NET Web application. The file is an XML document that defines
configuration information regarding the Web application. It contains information that control
module loading, security configuration, session state configuration, and application language and
compilation settings. Web.config files can also contain application specific items, such as database
connection strings. The example of Web.config is as follows:
<configuration>
<system.web>
<customErrors mode=”off” defaultRedirect=”mycustompage1.htm”/>
</system.web>
</configuration>
The Machine.config file controls the configuration settings for the entire computer. It includes
settings specific to a computer, such as built-in remoting channels, machine-wide assembly binding,
and ASP .NET configuration settings. The configuration system first searches for APIs and ASP .NET
settings in the machine.config file. The default configuration of the .NET Framework is declared in
the Machine.config file.
Answer C is incorrect. Global.asax is an optional file that contains code for responding to global
events that occur in a Web application. There can be only one Global.asax file for an application. This
file resides in the root directory of an ASP.NET application. External users cannot download or view
the code written within the Global.asax file.

Answer B is incorrect. Trace.axd is an Http Handler that can be used to view the trace details for an
application. This file resides in the application’s root directory. A request to this file through a
browser displays the trace log of the last n requests in time-order, where n is an integer determined
by the value set by requestLimit=”[n]” in the application’s configuration file.