CCNA Network Services and Security Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Enter global configuration mode, define the RADIUS server, configure AAA authentication, enable 802.1X globally, apply per-interface 802.1X settings.

  Why this is correct

  This is the correct sequence because the RADIUS server must exist before the AAA method list can reference it, AAA authentication must be in place before the global 802.1X switch is enabled, and per-interface enforcement comes last. In Cisco IOS, the commands 'radius server' defines the host and key, 'aaa authentication dot1x default group radius' builds the method list, 'dot1x system-auth-control' enables the feature globally, and then interface configuration with 'dot1x port-control auto' applies it. Skipping any earlier step would leave 802.1X referencing a missing server or no authentication method.

• ✗

  Enter global configuration mode, enable 802.1X globally, define the RADIUS server, configure AAA authentication, apply per-interface 802.1X settings.

  Why it's wrong here

  Enabling 802.1X globally with 'dot1x system-auth-control' before configuring AAA is premature because no authentication method list exists to validate supplicants; the switch would have no mechanism to authenticate users even though the feature is enabled. Furthermore, AAA authentication cannot be configured until the RADIUS server is defined, because 'aaa authentication dot1x default group radius' requires an existing RADIUS server group. Thus this sequence leaves a broken configuration and would not authenticate anyone.

• ✗

  Enter global configuration mode, configure AAA authentication, define the RADIUS server, enable 802.1X globally, apply per-interface 802.1X settings.

  Why it's wrong here

  Configuring AAA authentication before defining the RADIUS server is impossible in practice: the command 'aaa authentication dot1x default group radius' references a server group that does not yet exist, so the IOS would either reject the command or create an empty method list. In a proper configuration, the RADIUS server must be defined first so the AAA method list can point to a valid host with a shared key. This order also matters because AAA authentication for 802.1X must be present before the global 'dot1x system-auth-control' is issued, but the server definition and AAA configuration are tightly coupled and cannot be reversed.

• ✗

  Enter global configuration mode, define the RADIUS server, enable 802.1X globally, configure AAA authentication, apply per-interface 802.1X settings.

  Why it's wrong here

  Defining the RADIUS server first is correct, but enabling 802.1X globally before configuring AAA authentication still leaves the switch without a method list for dot1x; the 'dot1x system-auth-control' command activates 802.1X on all capable ports, but no 'aaa authentication dot1x' method list exists to specify RADIUS, so authentication requests would be unanswered. The AAA configuration must be inserted between the server definition and the global enable to provide the actual authentication mechanism. This is a classic ordering trap: the server definition alone does not enable any authentication flow.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

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