title: OpenSource tools/services for server monitoring
body: <p>I'm looking for an OpenSource server monitoring tool that allows the following:</p>
  
  <ul>
  <li>Monitor a variety of services on TCP, UDP.</li>
  <li>Supports custom port numbers.</li>
  <li>Supports some basic response checking (beyond initial connection checking).</li>
  <li>Basic dashboard overview of health status.</li>
  <li>Alert notifications via e-mail.</li>
  </ul>
  
  <p>I could roll my own, but want to make sure I don't reinvent the wheel if there's a complete suite out there that does what I want (and maybe more!).</p>
  
  <p><strong>EDIT</strong>: Preferably software that runs on Windows.</p>