title: Multiple smtphost addresses using smtpAppender in log4net
body: <p>I want to be able to specify multiple smtp server host addresses and implement a logic whereby if email using one smtp server fails, it tries to send using the next smtp server address. Is it possible using log4net. Can we override some functions of log4net and implement our own logic in it to send emails?</p>
  
  <pre><code>&lt;appender name="SmtpAppender" type="log4net.Appender.SmtpAppender"&gt;
    &lt;to value="group@ivp.in" /&gt;
    &lt;from value="uname@ivp.in" /&gt;
    &lt;subject&gt;Error Notification&lt;/subject&gt;
    **&lt;smtpHost value="10.0.0.12, 10.0.0.13" /&gt;**
    &lt;authentication value="None" /&gt;
    &lt;port value="25" /&gt;
    &lt;bufferSize value="1" /&gt;
    &lt;EnableSsl value="false"/&gt;
    &lt;lossy value="true" /&gt;
    &lt;evaluator type="log4net.Core.LevelEvaluator"&gt;
      &lt;threshold value="ERROR"/&gt;
    &lt;/evaluator&gt;
    &lt;layout type="log4net.Layout.PatternLayout"&gt;
      &lt;conversionPattern value="%newline%date [%thread] %level %logger - %message%newline%newline%exception" /&gt;
    &lt;/layout&gt;
  &lt;/appender&gt;
  </code></pre>