Dell PowerConnect 8100 User's Configuration Guide - Page 472

What is MAC-Based 802.1X Authentication? MAC-based authentication allows multiple supplicants connected to the same port to each authenticate individually. For example, a 5-port hub might be connected to a single port on the switch. Each host connected to the hub must authenticate separately in order to gain access to the network. The hosts are distinguished by their MAC addresses. NOTE: By default, all ports are in VLAN Access mode. A port that uses MACbased authentication should be configured to be in General mode. When multiple hosts (for example, a PC, a printer, and a phone in the same office) are connected to the switch on the same port, each of the connected hosts authenticates separately with the RADIUS server. If a port uses MAC-based 802.1X authentication, the option to use MAC Authentication Bypass (MAB) is available. MAB is a supplemental authentication mechanism that allows 802.1X unaware clients - such as printers, fax machines, and some IP phones - to authenticate to the network using the client MAC address as an identifier. The known and allowable MAC address and corresponding access rights of the client must be pre-populated in the authentication server. When a port configured for MAB receives traffic from an unauthenticated client, the switch (Authenticator): • Sends a EAP Request packet to the unauthenticated client • Waits a pre-determined period of time for a response • Retries - resends the EAP Request packet up to three times • Considers the client to be 802.1X unaware client (if it does not receive an EAP response packet from that client) The authenticator sends a request to the authentication server with the MAC address of the client in a hexadecimal format as the username and the MD5 hash of the MAC address as the password. The authentication server checks its database for the authorized MAC addresses and returns an Access-Accept or an Access-Reject response, depending on whether the MAC address is found in the database. MAB also allows 802.1X-unaware clients to be placed in a RADIUS-assigned VLAN or to apply a specific Filter ID to the client traffic. 472 Configuring Port and System Security