thanks. can you please give me a sample of custom route constraint? I have tried creating now a new route

            routes.MapRoute(
                "clientweb", // Route name
                "{id}", // URL with parameters
                new { controller = "Client", action = "Index" } // Parameter defaults
            );

this works. but now accessing Home controller does not work anymore.

my final goal on the site is to give user a personal page in format http://mysite/clientname

that is why it is optional, as if not provided the default page is displayd.