802.1X Authentication Initiation; 802.1X Client As The Initiator; Access Device As The Initiator - HP FlexNetwork 10500 Series Security Configuration Manual

Figure 29 EAP-Message attribute format
Message-Authenticator
As shown in
have an EAP-Message attribute to check their integrity. The packet receiver drops the packet if the
calculated packet integrity checksum is different from the Message-Authenticator attribute value.
The Message-Authenticator prevents EAP authentication packets from being tampered with during
EAP authentication.
Figure 30 Message-Authenticator attribute format

802.1X authentication initiation

Both the 802.1X client and the access device can initiate 802.1X authentication.

802.1X client as the initiator

The client sends an EAPOL-Start packet to the access device to initiate 802.1X authentication. The
destination MAC address of the packet is the IEEE 802.1X specified multicast address
01-80-C2-00-00-03 or the broadcast MAC address. If any intermediate device between the client
and the authentication server does not support the multicast address, you must use an 802.1X client
that can send broadcast EAPOL-Start packets. For example, you can use the HPE iNode 802.1X
client.

Access device as the initiator

The access device initiates authentication, if a client cannot send EAPOL-Start packets. One
example is the 802.1X client available with Windows XP.
The access device supports the following modes:
•
Multicast trigger mode—The access device multicasts Identity EAP-Request packets to
initiate 802.1X authentication at the identity request interval.
•
Unicast trigger mode—Upon receiving a frame from an unknown MAC address, the access
device sends an Identity EAP-Request packet out of the receiving port to the MAC address. The
device retransmits the packet if no response has been received within the identity request
timeout interval. This process continues until the maximum number of request attempts set by
using the dot1x retry command is reached.
The username request timeout timer sets both the identity request interval for the multicast trigger
and the identity request timeout interval for the unicast trigger.
Figure 30, RADIUS includes the Message-Authenticator attribute in all packets that
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