In the case of a 301 redirect, the web server responds to the requesting client that the requested URL has been moved permanently (“301 moved permanently“) and can be reached under a new URL.
Technically speaking, a 301 redirect transmits the HTTP status code “301 Moved Permanently”. By transmitting this 301 status code, the web server forwards all requests from a source URL to a new destination URL.
For users and clients, a 301 redirect has the advantage that they do not end up on a 404 error page, but are taken to the desired – originally requested – resource (on its new URL).
A 301 redirect remains almost unnoticed by the user, as only the URL in the address bar of the web browser changes and the request takes slightly longer – on average just under 0.2 seconds per redirect.
The 301 Redirect Process Explained
The following diagram explains the technical process of a 301 redirect.
What happens during a 301 redirect?
- The Googlebot would like to retrieve the file “abc.html” from the domain “domain.com”.
- The Googlebot sends a request to the web server of the domain “domain.com” and asks for the file “abc.html”.
- The web server notices that the file “abc.html” does not exist any more on the URL “domain.com/abc.html”. In addition, the web server realises that there is an existing 301 redirect for the file “abc.html” to “xyz.html”.
- The web server returns the HTTP status code 301 (Moved Permanently) to the Googlebot and points to the new URL, “domain.com/xyz.html”.
- The Googlebot understands that the content of the file “domain.com/abc.html” can now be found at the URL “domain.com/xyz.html”. From now on, when trying to access the file “domain.com/abc.html”, a user will be redirected automatically to “domain.com/xyz.html”.
When should I use a 301 redirect?
The use of a 301 redirect always makes sense when the URL structure of a website changes or even the entire domain name is changed. It also makes sense when a website is merged with another or the content of a website can be accessed via two different URLs.
301 Redirects Do Not Have a High Damping Factor
According to Matt Cutts, former head of Google’s webspam team, a redirect using the HTTP status code 301 (Moved Permanently) does not have a higher damping factor than that for links. Accordingly, redirecting internal and external links using a 301 redirect is a good choice.
What Google says
If you need to change the URL of a page as it is shown in search engine results, we recommend that you use a permanent server-side redirect whenever possible. This is the best way to ensure that Google Search and people are directed to the correct page. The 301 and 308 status codes mean that a page has permanently moved to a new location.
Our Conclusion
If a page moves permanently, always use a 301 redirect. The redirect type 301 (Moved Permanently) indicates that a resource can be found permanently in a different location, and future requests should use the new URL.
