title: SPItemEventReceiver Context SiteId/WebUrl Incorrect
body: <p>I have created a SharePoint Event Receiver, that fires on Item Update.
  The receiver needs access AfterProperties and ListItem.</p>
  
  <p>When firing the event receiver from a SharePoint web application using an IP address (<a href="http://10.0.4.50/sites/" rel="nofollow noreferrer">http://10.0.4.50/sites/</a>), it throws a <strong>FileNotFoundException</strong>, when accessing SiteId And WebUrl in SPItemEventProperties.
  <em>The Web application at <a href="http://10.0.4.50/sites/companyName" rel="nofollow noreferrer">http://10.0.4.50/sites/companyName</a> could not be found. Verify that you have typed the URL correctly.</em></p>
  
  <p>When firing the event receiver using the hostname, specified at setup of Site Collection <strong><a href="http://computerhostname/sites/companyName" rel="nofollow noreferrer">http://computerhostname/sites/companyName</a></strong>. This works fine, no exception is thrown.</p>
  
  <pre><code>//Combine Both AfterProperties And ListItem
  var ListProperties = new List&lt;KeyValuePair&lt;string, object&gt;&gt;();
  ListProperties.AddRange(properties.AfterProperties.ToKeyValue());
  ListProperties.AddRange(properties.ListItem.ToKeyValue(p =&gt; !p.Sealed));
  var AvaliableProperties = ListProperties.Distinct(new KeyValueComparer&lt;object&gt;());
  </code></pre>