The incoming host header is stored in the server variable "HTTP_HOST", and the Redirect method of the Response object is used to perform the redirection.

For example, the following code will examine the host header and redirect to a subfolder.

<%
Option Explicit
Response.Buffer = True 

Dim HostURL
HostURL = Lcase(Request.ServerVariables("HTTP_HOST")) 

Select Case HostURL ' Find which site to redirect to
 Case "www.widgets.com", "widgets.com"
 Response.Redirect("widgets/default.htm")
 Case "www.tiddleywinks.com", "tiddleywinks.com"
 Response.Redirect("tiddleywinks/default.htm")
 Case "www.fiddlesticks.com", "fiddlesticks.com"
 Response.Redirect("fiddlesticks/default.htm")
End Select

%>

If you use relative URL's in your Redirect statements as shown above, the client browser will continue to use the original alias domain name. In other words, by using URL's like "/this" or "/that" the original alias domain name will appear in the client web browser URL bar after the redirect has completed.

If your redirect parameter looks like "http://www.this.that" then the value in the client browser will show the full URL used in the redirect, not the one from the original request to your alias.