In wifi,user is trying to access ssid by using wifi security protocols

[palani2010]

In wireless technologies, user is trying to access ssid by using wireless security protocols.

Question.

Authentication comes first or else user client request obtain ip address from DHCP server.

Can some one explain me in simple terms as I am getting different answers from different people I am so confused.

[Haydn Andrews · Accepted solution]

First user associates to the SSID

For Layer 2 Authentication (Preshared Key, 802.1x)
Authentication happens first and only if successful then access to the network then DHCP

For Layer 3 Authentication (Captive Portals)

DHCP happens first, then redirect to portal

this is why you need a pre-auth ACL to prevent users accessing anything other than DHCP, DNS and the portal.