where to put redirecting script

Please where do I put the redirecting script.
Is it inside the default.aspx page of the sub folder i created or the default.aspx page of my main root website


You can use this script to redirect
<%
If InStr( UCase(Request.ServerVariables("SERVER_NAME")),  UCase("mayflowerblogger.yourdomain.com") ) > 0 Then
        Response.Redirect("/mayblogger")
Else
    Response.Redirect("/somefile.aspx")
End If
%>
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