Redirect any pages in a old site to corresponding pages in new site

This mostly involves moving a site to another hosting company, since we can't simply change the IP address of the new server to be the DNS-registered IP. DNS will be changed to the new IP but it takes hours for it to populate to all ISPs. We can blindly redirect all request to the home page of the new server, but that means no matter what page/querystring user requests, he/she will see the home page. Not very user friendly.

Step 1: register a new sub domain (e.g. new.myblog.com), so that user's ISP will get the brand new IP address.

Step 2: in old server, add a Wildcard application maps to have ASP.NET engine handle all requests (html, gif etc)

Step 3: in global.asax, redirect user in Application_BegineRequest:

string url = HttpContext.Current.Request.Url.AbsolutePath;
string QueryParams = HttpContext.Current.Request.QueryString.ToString();
if ( QueryParams != "")
{ Response.Redirect("http://new.myblog.com" + url + "?"+ QueryParams); }
else
{ Response.Redirect("http://new.myblog.com" + url ); }