public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)                                                      //crea il web host predefinito
                .ConfigureAppConfiguration((hostingContext, config) =>
                {
                    config.SetBasePath(Directory.GetCurrentDirectory());
                    config.AddJsonFile("Hosting.json", optional: false);
                })
                .UseStartup<Startup>();

{
  "urls": "http://*:80; http://localhost:5000"
}

.UseUrls("http://*:80", "http://localhost:5000")

{
    "urls": "http://*:5001;http://localhost:5555"
}

var config = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddInMemoryCollection(configObject)
                .AddJsonFile("hosting.json")
                .AddEnvironmentVariables("ASPNETCORE_")
                .Build();