301

The HTTP response status code 301 Moved Permanently is used for permanent URL redirection, meaning current links or records using the URL that the response is received for should be updated. The new URL should be provided in the Location field included with the response. The 301 redirect is considered a best practice for upgrading users from HTTP to HTTPS.RFC 2616 states that:
If a client has link-editing capabilities, it should update all references to the Request URL.
The response is cacheable unless indicated otherwise.
Unless the request method was HEAD, the entity should contain a small hypertext note with a hyperlink to the new URL(s).
If the 301 status code is received in response to a request of any type other than GET or HEAD, the client must ask the user before redirecting.

View More On Wikipedia.org