Should I perform a 301 redirect in Global.asax or on my 404 error page
<p>I'm about to replace a current e-commerce site with a brand new site. Before, a URL to a product was like this: www.example.com/ProductDetails.aspx?ProductID=123</p>

<p>Now it is like this: www.example.com/en-us/product/123/The-greatest-product-in-the-world</p>

<p>My question is: Should the 301 permanent redirect be done in the Application_BeginRequest event of Global.asax or in the Page_Load of my 404 error page? Isn't too late to make a 301 when the 404 loads?</p>
