EAPOL
Extensible Authentication Protocol over Local Area Network (EAPoL) is one of the message formats from the Extensible Authentication Protocol (EAP) authentication protocol. Other EAP message formats are "EAP over Wireless (EAPoW)" and "EAP over Point-to-Point-Protocol (EAPoPPP)".
The EAP comes from the time when computers were still directly connected to each other via a modem and a (telephone) line and communicated via the PPP protocol ( Point-to-Point Protocol ). This is why EAPOL exists so that EAP can also be used for local area networks.
EAP is an RFC standardized protocol, whereas EAPOL is part of the IEEE 802.1X standard. More precisely: EAPOL is one of the core protocols of the IEEE 802.1X standard. Currently (March 2005) EAPOL is intended for the use of Ethernet- like networks, in particular for wireless 802.11 networks, as well as token-ring networks (such as FDDI ).
EAPOL is usually used between a supplicant ( e.g. a notebook with a WLAN card) and an authenticator ( e.g. an access point). Here, the EAP packets for the exchange of authentication information are encapsulated in Ethernet frames in order to enable EAP communication via a Layer 2 connection. The terms supplicant and authenticator come from the 802.1X environment.