3Com S7906E - Switch, Configuration Manual

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Direct authentication/Layer 3 authentication process
Figure 1-2 Direct authentication/Layer 3 authentication process
The direct authentication/Layer 3 authentication process is as follows:
1) A portal user initiates an authentication request through HTTP. When the HTTP packet arrives at
the access device, the access device allows it to pass if it is destined for the portal server or a
predefined free website, or redirects it to the portal server if it is destined for other websites. The
portal server provides a web page for the user to enter the username and password.
2) The portal server and the access device exchange Challenge Handshake Authentication Protocol
(CHAP) messages. For Password Authentication Protocol (PAP) authentication, this step is
skipped.
3) The portal server assembles the username and password into an authentication request message
and sends it to the access device. Meanwhile, the portal server starts a timer to wait for an
authentication acknowledgment message.
4) The access device and the RADIUS server exchange RADIUS packets to authenticate the user.
5) If the user passes authentication, the access device sends an authentication acknowledgment
message to the portal server.
6) The portal server sends an authentication acknowledgment message to the authentication client to
notify it of logon success.
7) The portal server sends an affirmation message to the access device.
With extended portal functions, the process includes two additional steps:
8) The security policy server exchanges security authentication information with the client to check
whether the authentication client meets the security requirements.
9) The security policy server authorizes the user to access unrestricted resources based on the
security configuration for the user. The authorization information is stored on the access device
and used by the access device to control user access.