Hopefully you can now see a little bit about how the "flow" of the security

context works:

#. the Firewall is registered as a listener on thereques;

#. the Firewall is registered as a listener on the``kernel.request`` event;

#. at the beginning of the request, the Firewall checks the firewall map

to see if any firewall should be active for this URL;

#. If a firewall is foundon the map for this URL, its listeners are notified

#. If a firewall is foundin the map for this URL, its listeners are notified

#. each listener checks to see if the current request contains any authentication

information - a listener may (a) authenticate a user, (b) throw an

``AuthenticationException``, or (c) do nothing (because there is no

authentication information on the request);

#. Once a user isauthentication, you'll use:doc:`/components/security/authorization`

#. Once a user isauthenticated, you'll use:doc:`/components/security/authorization`

to deny access to certain resources.

Read the next sections to find out more about:doc:`/components/security/authentication`