There’s a problem with 401 Unauthorized, the HTTP status code for authentication errors. And that’s just it: it’s for authentication, not authorization. Receiving a 401 response is the server telling you, “you aren’t authenticated–either not authenticated at all or authenticated incorrectly–but please reauthenticate and try again.” To help you out, it will always include a WWW-Authenticate header that describes how to authenticate.

This is a response generally returned by your web server, not your web application.

It’s also something very temporary; the server is asking you to try again.

So, for authorization I use the 403 Forbidden response. It’s permanent, it’s tied to my application logic, and it’s a more concrete response than a 401.

Receiving a 403 response is the server telling you, “I’m sorry. I know who you are–I believe who you say you are–but you just don’t have permission to access this resource. Maybe if you ask the system administrator nicely, you’ll get permission. But please don’t bother me again until your predicament changes.”

In summary, a 401 Unauthorized response should be used for missing or bad authentication, and a 403 Forbidden response should be used afterwards, when the user is authenticated but isn’t authorized to perform the requested operation on the given resource.

Well that’s my view on it anyway :)

Tagged with:
 

One Response to Understanding 403 Forbidden

  1. Erwan Legrand says:

    This is not the IETF’s view on the matter. See for example here

    If the request included authentication credentials, then the 401 response indicates that authorization has been refused for those credentials.

    403 is used to deny access to resources which are not meant to be accessed over HTTP, or can’t be accessed from the client’s IP range, or can be access only over HTTPS… anything which does not involve authentication.

Leave a Reply

Your email address will not be published. Required fields are marked *


*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>