title: identityserver on multiple URLs
body: <p>I have 2 sites. siteA.com and siteB.com, both resolved to the same IIS application. 
  Identityserver is abailable on siteA.com/Login, I set it up like this:</p>
  
  <pre><code>    app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions
      {
          AuthenticationType = "oidc",
          SignInAsAuthenticationType = "Cookies",
  
          Authority = siteA.com/Login,
          ...
      }
  </code></pre>
  
  <p>so if I go to siteB.com, it also redirects me to siteA.com/Login.</p>
  
  <p>I can't use HttpContext.Current.Request here, because it returns local ip address, as this code runs once, setting up the middleware.</p>
  
  <p>Can I somehow redirect from siteA.com to siteA.com/login, and from siteB.com to siteB.com/Login?</p>
  
  <p>thanks</p>