Solution #596 - How do I enable log4net internal debugging?

First, add the log4net.Internal.Debug key to the appSettings section of your application’s configuration file (such as web.config):

<configuration>
   <appSettings>
      <add key="log4net.Internal.Debug" value="true"/>
   </appSettings>
</configuration>

Second, add a system.diagnostics section (if it doesn’t already exist) to the same config file, and define the location where log4net logs should be written to:

<configuration>
...
<system.diagnostics>
    <trace autoflush="true">
        <listeners>
            <add 
                name="textWriterTraceListener" 
                type="System.Diagnostics.TextWriterTraceListener" 
                initializeData="C:\temp\log4net.log" />
        </listeners>
    </trace>
</system.diagnostics>
...
</configuration>

Additional information is available under ‘How do I enable log4net internal debugging?’ in the log4net FAQ page:
http://logging.apache.org/log4net/release/faq.html