How do search engines react when you change a 301 redirect?

June 10, 2006 11:05 AM

How do search engines react when you change a 301 redirect?

Let's suppose that you had a permanent redirect on your website:

http://www.foobar.com/old/ --> http://www.foobar.com/new/

The /old/ link was quite popular prior to implementing the redirect and, after implementing the 301, search engines consolidated the rankings for /old/ and /new/ URIs. But what happens when you want to change that redirect? For example:

http://www.foobar.com/old/ --> http://www.foobar.com/newer/

Supposing that /old/ remains heavily linked on 3rd party sites, will common search engine spiders pick up the change or do they somehow cache the 301 redirection (which is, afterall, "permanent")?

To be safe, I suppose one could simply add another 301 redirect for /new/ --> /newer/, but the above example is an oversimplification. For the sake of discussion, let's suppose that I have tens of thousands of 301 redirects the targets of which may need to change at some point in the future making it difficult to add that secondary redirect.

1.) Do search engine spiders regularly check a URL that returns a 301 -- even if people still link to that URL?
2.) If so, will changing the target of redirection negatively effect page rankings?

posted by HAMFIST to Computers & Internet (2 answers total)

I can't say for certain, but any sensible search engine is going to check old 301s; particularly if people are still linking to them. It may take weeks for the new redirect to be recognized, but I wouldn't sweat it.
posted by Nelson at 12:18 PM on June 10, 2006

Perhaps issuing a Last-Modified header would help expedite the invalidation process?
posted by HAMFIST at 12:28 PM on June 10, 2006