802.1X

Port-based network access control, the standard for authenticating users and devices onto wired and wireless networks. Articles tagged 802.1X cover supplicant and authenticator behavior, RADIUS, EAP methods, Cisco ISE, dynamic VLANs, dACLs, host modes, and phased deployment.

33 posts

802.1X

Cisco ISE 802.1x Wired Configuration: A Practical Step-by-Step Guide

A complete, copy-pasteable walkthrough of deploying wired 802.1x with Cisco ISE as the RADIUS server and a Catalyst switch as the authenticator — from Policy Sets to IBNS 2.0 CLI to show commands and Live Logs.

Apr 20, 2026 12 min read

Wireless

How to Configure 802.1X and WPA3 Enterprise on the Cisco C9800

802.1X plus WPA3 Enterprise gives you mutual authentication, granular access, and protection against modern wireless attacks. A step-by-step Cisco Catalyst 9800 configuration guide for secure enterprise wireless.

Apr 5, 2026 10 min read

802.1X

Understanding RADIUS in 802.1X Authentication

RADIUS is the glue between a Catalyst switch and Cisco ISE in 802.1X. Here is how the Access-Request carries EAP, why UDP 1812/1813 matters, and where failures surface.

Mar 24, 2026 9 min read

802.1X

EAPOL Explained: How 802.1X Traffic Moves Over the Wire

EAPOL carries EAP between the supplicant and switch at Layer 2. It never leaves the segment, which is why captures and debug have to happen on or at the port.

Mar 24, 2026 8 min read

802.1X

How EAP Works in 802.1X: EAP Methods Compared

EAP is a framework, not a protocol. Compare EAP-TLS, PEAP-MSCHAPv2, EAP-FAST, and EAP-TTLS by credential type, tunnel, and where each belongs in enterprise 802.1X.

Mar 24, 2026 9 min read

802.1X

802.1X Components Explained: Supplicant, Authenticator, and Authentication Server

802.1X splits work across three roles: supplicant, authenticator, and authentication server. Understanding the boundaries explains both the config and the failure points.

Mar 24, 2026 9 min read