What is 802.1X authentication?
D3 · Architecture · CompTIA Security+ SY0-701802.1X is an IEEE standard for port-based Network Access Control (NAC) that requires devices to authenticate before being granted access to a wired or wireless network port.
Three components: Supplicant (client device), Authenticator (switch or AP), Authentication Server (RADIUS/LDAP).
Flow: Supplicant connects → Authenticator blocks access → prompts for credentials → forwards to RADIUS server → if authenticated, port opens.
Used in: enterprise Wi-Fi (WPA2/3-Enterprise), wired network port security.
Three components: Supplicant (client device), Authenticator (switch or AP), Authentication Server (RADIUS/LDAP).
Flow: Supplicant connects → Authenticator blocks access → prompts for credentials → forwards to RADIUS server → if authenticated, port opens.
Used in: enterprise Wi-Fi (WPA2/3-Enterprise), wired network port security.
802.1X prevents unauthorized devices from connecting to your network. Combined with EAP (Extensible Authentication Protocol) for the actual authentication method. EAP-TLS (certificate-based) is the most secure EAP type. Without 802.1X, anyone can plug into a network jack.