Implementing Custom 404 page in ASP.NET Web Form Application using Routing

Hello,

I am using ASP.NET 4.0 Web Forms. I learned that, in order to optimize my Web Application for Search Engine, I must implement custom 404 page. But the way Microsoft tell us to implement custom 404 (within Web.Config file), that is not good for SEO. Microsoft says,


<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm"> <error statusCode="404" redirect="Page-Not-Found.aspx" /> </customErrors>
But when the page is not found, IIS issue 302 redirect to Page-Not-Found.aspx page which is not good. So, I implemented custom 404 page using Routing technique that ...