Redirect(relativeUrl) redirecting to wrong path in IIS

Question

In the usual AccountController in my MVC3 app, if returnUrl is set (in my case, I set it manually), it will call Redirect(returnUrl).

Assume my return URL is /Admin/HealthCheck (which it really is). When I'm debugging, I get a URL like http://localhost:3279/Admin/HealthCheck from the redirect call.

Then, I deployed my app to http://localhost/Test. In this case, Redirect(returnUrl) redirects me to http://localhost/Admin/HealthCheck and not the expected http://localhost/Test/Admin/HealthCheck.

What's going on here? How do I fix this (if it is fixable)?

Below is a snippet from the (standard) MVC3 AccountController; you can see where I get the return URL from the query string (eg. http://localhost/Test/LogOn?ReturnUrl=/Admin/HealthCheck, albeit URL encoded).

[HttpPost]
        public ActionResult LogOn(LogOnModel model, string returnUrl)
        {
            if (ModelState.IsValid)
            {
                if (Membership.ValidateUser(model.UserName, model.Password))
                {
                    returnUrl = Request.Params["ReturnUrl"];

                    FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
                    if (Url.IsLocalUrl(returnUrl) && returnUrl.Length > 1 && returnUrl.StartsWith("/")
                        && !returnUrl.StartsWith("//") && !returnUrl.StartsWith("/\\"))
                    {
                        return Redirect(returnUrl);
                    }
                    else
                    {
                        return RedirectToAction("Index", "Home");
                    }
                }
                else
                {
                    ModelState.AddModelError("", "The user name or password provided is incorrect.");
                }
            }

Answer 1

(in my case, I set it manually)

You haven't actually shown how this manual setting happens, but if you have hardcoded an url such as /Admin/HealthCheck instead of using an url helper to generate this url such as Url.Action("HealthCheck", "Admin") don't expect miracles to happen.

Your LogOn is fine. It does what it is supposed to do => it redirects to the url that is passed as argument. Your problem lies in the way you are setting this url.

Conclusion: in an ASP.NET MVC application always use url helpers when dealing with urls. Never hardcode them.