The client (browser or bot) will have no idea what happened Server.Transfer. He will see that he requested the given URL and received the content you returned. There is no response to the client saying that you moved things (that would be Response.Redirect).
In your case, it sounds like this means that you will have two URLs returning the same content - two identical pages - which can affect how search indexes handle the content (and, of course, means that you end up with people linking to both URLs, which may affect the rank of each URL).
, , URL- . Google, , http://example.com/foo.aspx, http://example.com/bar.aspx, , , () URL- http://example.com/bar.aspx, , :
<link rel="canonical" href="http://example.com/bar.aspx" />