I have a two Websites DNN  Based and general asp.net website external website, that contain a form to verify DNN user credential... If u write dnn Username Password on the form on ASP:Net website its should show correct username or wrong user name based on credentials.

Now the problem is how can i communicated between DNN and asp.net site ,exchanging username and password??? 

i know the code to do the manual authenticated using below code

UserLoginStatus loginStatus = new UserLoginStatus();
UserInfo objUserInfo = UserController.ValidateUser(PortalId, "txtUserName", "txtPassword", "", "", Request.UserHostAddress, ref loginStatus);

                    //Login Error
                    if (objUserInfo == null)
                    {
                        //"incorrect username or password";                       
                    }
                    else
                    {
                        //Successful login
                    }

but how can i achieve it by sitting in on ASP.Net website ???