About 802.1X - HP ProCurve NAC 800 User Manual

802.1X Quarantine Method

About 802.1X

11-2

About 802.1X

802.1X is a port-based authentication protocol that can dynamically vary
encryption keys, and has three components as follows:
■ Supplicant – The client; the endpoint that wants to access the
network.
Authenticator– The access point, such as a switch, that prevents
■
access when authentication fails. The authenticator can be simple and
dumb.
■ Authentication server – The server that authenticates the user creden-
tials; usually a Remote Authentication Dial-In User Service (RADIUS)
server.
802.1X is an authentication framework that sends Extensible Authentication
Protocol (EAP) messages packaged in Ethernet frames over LANs (EAPOL).
This method provides a savings in overhead resources because it does not use
all of the resources the typical Point-to-Point protocol requires.
EAP supports multiple authentication methods such as:
■ Kerberos – An authentication system that uses an encrypted ticket to
authenticate users.
One-time passwords – An authentication system that uses a set of
■
rotating passwords, each of which is used for only one login session.
■ Certificates – A method for identifying a user that links a public key
to the user's or company's identity, allowing them to send digitally
signed electronic messages.
Tokens – A credit-card or key-fob sized authentication endpoint that
■
displays a number that is synchronized with the authentication server.
The number changes over time, and the user is required to enter the
current number as part of the authentication process.
■ Public key authentication – In an asymmetric encryption system, two
keys are required; a public key and a private key. Either key can
encrypt and decrypt messages, but cannot encrypt and decrypt the
same message; that is, if the public key encrypts a message, the private
key must decrypt the message.
The typical 802.1X connections are shown in Figure 11-1 on page 11-3; The
typical communication flow is as follows:
1. A Client (supplicant) requests access from the access point (AP)
(authenticator).