Is Server.Transfer invisible to Google?

Question

I want to make some changes to my web site that requires some URL rewriting to keep my old URLs. I can't use proper URL rewriting because I have very limited control from my hosting provider.

As I'm using ASP.NET and all of my pages have the .aspx extension, one idea I had is to put something in the global.asax under the Application_BeginRequest event. This could check if the URL of the page requested is one of the old ones and use Server.Transfer to open the correct page.

My question is, would this transfer this invisible to Google? I don't want my ranking within Google to be affected.

Answer 1

Server.Transfer happens entirely on the server side, so any client (including Google) will not be aware of it.

Answer 2

The client (browser or bot) won't have any idea whatsoever that the Server.Transfer occurred. It will see only that it requested a given URL and got the content you return. There's no response to the client saying that you've moved things (that would be Response.Redirect).

In your case, it sounds like that would mean you'll have two URLs returning the same content — two identical pages — which could affect how search indexes treat the content (and certainly means you'll end up with people linking to both URLs, which could impact the rank of each URL).

You can address that by specifying what the canonical URL for the content is. More in this Google blog post, but basically, if you have both http://example.com/foo.aspx and http://example.com/bar.aspx returning the same content, and you want the canonical (official) URL to be http://example.com/bar.aspx, tell the indexers that:

<link rel="canonical" href="http://example.com/bar.aspx" />