350-701 Practice Question: Secure Network Access, Visibility and Enforcement
An engineer notices that the 'show authentication sessions' command on a switch shows a session in 'CRITICAL' state. What does this indicate?
⚠ Common exam trap
Cisco often tests the distinction between 'CRITICAL' (server unreachable) and 'AUTH_FAILED' (server reachable but rejects the host), so candidates mistakenly choose the rejected authentication option when they see 'CRITICAL'.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The authentication server is unreachable and the port is using the critical VLAN
The 'CRITICAL' state in 'show authentication sessions' indicates that the switch port has lost connectivity to the authentication server (RADIUS) and has fallen back to the configured critical VLAN. This is a failover mechanism defined in IEEE 802.1X and Cisco's critical-auth feature, where the port is placed into a pre-configured VLAN to maintain network access for the host despite the server being unreachable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The host is being authenticated via MAB
Why it's wrong here
MAB would show 'Running' or 'Authc in progress'.
- ✓
The authentication server is unreachable and the port is using the critical VLAN
Why this is correct
CRITICAL state indicates critical fallback.
- ✗
The port is administratively down
Why it's wrong here
Would show 'Down' state.
- ✗
The authentication attempt was rejected by the RADIUS server
Why it's wrong here
That would show 'Authz Failed' or 'Unauthorized'.
Visual reference
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-701 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-701 exam.