IEEE 802.1X是IEEE制定关于用户接入网络的认证标准（注意：此处X是大写），全称是“基于端口的网络接入控制”，属于IEEE 802.1网络协议组的一部分。于2001年标准化，之后为了配合无线网络的接入进行修订改版，于2004年完成。它为想要连接到LAN或WLAN的设备提供了一种认证机制。

IEEE 802.1X协议在用户接入网络（可以是以太网／802.3或者WLAN网）之前运行，运行于网络中的数据链路层，EAP协议RADIUS协议。

IEEE 802.1X定义了在IEEE 802上运行EAP（即"EAP over LAN"或EAPOL）的封装方式。EAPOL最初被定义在802.1X-2001，设计对象为IEEE 802.3以太网，但是后来为了适应其他IEEE 802 LAN技术，如IEEE 802.11无线和光纤分布式数据接口（FDDI）（ISO 9314-2），在802.1X-2004中又做了澄清。为了与IEEE 802.1AE (“MACsec”)和IEEE 802.1AR (Secure Device Identity, DevID)一起使用，EAPOL协议在802.1X-2010中还进行了修改，以支持服务识别和在本地LAN段上的可选点对点加密。

IEEE 802.1X is an IEEE Standard for port-based Network Access Control (PNAC). It is part of the IEEE 802.1 group of networking protocols. It provides an authentication mechanism to devices wishing to attach to a LAN or WLAN.

IEEE 802.1X defines the encapsulation of the Extensible Authentication Protocol (EAP) over IEEE 802, which is known as "EAP over LAN" or EAPOL. EAPOL was originally designed for IEEE 802.3 Ethernet in 802.1X-2001, but was clarified to suit other IEEE 802 LAN technologies such as IEEE 802.11 wireless and Fiber Distributed Data Interface (ISO 9314-2) in 802.1X-2004. The EAPOL protocol was also modified for use with IEEE 802.1AE (“MACsec”) and IEEE 802.1AR (Secure Device Identity, DevID) in 802.1X-2010 to support service identification and optional point to point encryption over the local LAN segment.