title: Will all requests that appear in HttpErr logs also appear in the IIS logs, by default?
body: <p>I'm maintaining a website that seems to be generating a lot of connection dropped errors in the HttpErr logs.  I'm trying to match up the errors in the HttpErr logs with log entries in the IIS logs, to see what additional information I can glean (eg time taken, response status code).</p>
  
  <p>I'm having trouble matching up records in the HttpErr logs with the corresponding requests in the IIS logs.  Although I can see requests from the same IP address in both logs, there seems to be no exact match between the timestamps in the two logs.  As a result I can't be sure if a request in the IIS log corresponds to an error in the HttpErr log, or whether they represent two different requests to the same page by the same user.  </p>
  
  <p>My question is: Will requests that appear as connection dropped errors in the HttpErr logs also appear in the IIS logs?  Or is it an either/or situation, where a request that has the connection dropped is logged to HttpErr but one that completes without the connection being dropped is logged to the IIS logs?</p>
  
  <p>I've had a look at the httpLogging element in the ApplicationHost.config and that has no selectiveLogging attribute.  I understand that to mean IIS should log all requests by default.  However, does "all" really mean every single request, including those where the connection has been dropped?</p>