title: WebAPI OWIN SelfHosting CORS support
body: <p>I am using Microsoft.AspNet.WebApi V5.2.3, Microsoft.Owin.Host.HttpListener 3.0.1. Started with the following configuration:</p>
  
  <pre><code>public void Configuration(IAppBuilder appBuilder)
  {
      HttpConfiguration config = new HttpConfiguration();
      config.MapHttpAttributeRoutes();
  
      appBuilder.UseWebApi(config);
  }
  </code></pre>
  
  <p>And the API Controller class is declared using:</p>
  
  <pre><code>[EnableCors("*", "*", "*")]
  public class CWebAPIController : ApiController
  {
      [Route("API/System/Login"), HttpGet]
      public IHttpActionResult Login(string UserID, string Password)
      {
          .... bla bla bla .....
      }
  }
  </code></pre>
  
  <p>I am able to invoke the API above using HttpClent on the same computer, but if I trying to invoke the API from another computer (within the same subnet), I got 400 BadRequest response.</p>
  
  <p>I believe this is CORS issue, but may I know how can I solve this. Searching in google yield many results and there are so many version / implementation of WebApi that I don't know which one is correct after trying one whole day.</p>
  
  <p>Thanks in advance</p>