app.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>

  <log4net>
    <appender name="udp" type="log4net.Appender.UdpAppender">
      <RemoteAddress value="127.0.0.1"/>
      <RemotePort value="9998"/>
      <LocalPort value="23451"/>
      <layout type="log4net.Layout.XmlLayout">
        <locationInfo value="true" />
      </layout>
    </appender>

    <appender name="console" type="log4net.Appender.ColoredConsoleAppender">
      <layout type="log4net.Layout.SimpleLayout"/>
      <mapping>
        <level value="FATAL"/>
        <foreColor value="Yellow, HighIntensity"/>
        <backColor value="Red"/>
      </mapping>
      <mapping>
        <level value="ERROR"/>
        <foreColor value="Red, HighIntensity"/>
      </mapping>
      <mapping>
        <level value="WARN"/>
        <foreColor value="Yellow, HighIntensity"/>
      </mapping>
      <mapping>
        <level value="INFO"/>
        <foreColor value="Cyan"/>
      </mapping>
      <mapping>
        <level value="DEBUG"/>
        <foreColor value="White"/>
      </mapping>
    </appender>    

    <root>
      <level value="DEBUG"/>
      <appender-ref ref="udp"/>
      <appender-ref ref="console"/>
    </root>
  </log4net>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>