title: How can I tell if I have an open relay?
body: <p>I'm trying to work out if I have an open relay on my server. How do I do that?</p>
  
  <p>I've tried <a href="http://www.abuse.net/relay.html" rel="nofollow noreferrer">http://www.abuse.net/relay.html</a></p>
  
  <p>and it reports:</p>
  
  <p>Hmmn, at first glance, host appeared to accept a message for relay.
  THIS MAY OR MAY NOT MEAN THAT IT'S AN OPEN RELAY.
  Some systems appear to accept relay mail, but then reject messages internally rather than delivering them, but you cannot tell at this point whether the message will be relayed or not.</p>
  
  <p>What further tests can I do to determine if the server has an open relay?</p>