The correct answer is that this configuration enables CTS inline tagging with a pre-shared key for SGT exchange between peers. The `cts manual` command under the interface places the port in manual TrustSec mode, while the `sap pmk` parameter defines a pre-shared key (PMK) used to authenticate and encrypt Security Group Tag (SGT) information between directly connected Cisco switches. The `mode-list both` directive allows the interface to both source and enforce SGTs, meaning it can tag outgoing frames and inspect incoming ones for role-based access control. On the ENCOR 350-401 exam, this question tests your understanding of TrustSec manual mode as a simpler, static alternative to 802.1X or MACsec—common traps include confusing `pmk` with RADIUS-based keying or forgetting that `mode-list both` is required for bidirectional enforcement. A helpful memory tip: think of “PMK” as “Pre-shared Manual Key” and “both” as “both directions,” ensuring you remember that manual mode uses a static key for SGT propagation without a central authentication server.
350-401 802.1X and TrustSec Practice Question
This 350-401 practice question tests your understanding of 802.1x and trustsec. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Consider the following TrustSec configuration on a Cisco switch:
cts role-based enforcement
interface GigabitEthernet1/0/3
cts manual
sap pmk 0123456789ABCDEF mode-list both
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It enables CTS inline tagging with a pre-shared key for SGT exchange between peers.
This enables CTS role-based enforcement globally and configures the interface for manual CTS with a pre-shared key (PMK) for SGT exchange. The 'mode-list both' allows both source and destination SGT enforcement.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
It enables 802.1X authentication with a pre-shared key.
Why it's wrong here
This is TrustSec, not 802.1X; the PMK is used for SGT propagation.
✗
It configures the interface to use SGT (Security Group Tag) propagation via SXP.
Why it's wrong here
SXP is a different protocol; this uses SAP (Security Association Protocol) for inline tagging.
✓
It enables CTS inline tagging with a pre-shared key for SGT exchange between peers.
Why this is correct
The 'cts manual' with 'sap pmk' configures manual TrustSec with inline SGT tagging using a pre-shared key.
Related concept
Access ports place end devices into a single VLAN.
✗
It enables dynamic VLAN assignment based on user authentication.
Why it's wrong here
This configuration is for TrustSec, not VLAN assignment.
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
Access ports place end devices into a single VLAN.
Trunk ports carry multiple VLANs between switches.
Allowed VLAN lists decide which VLANs can cross a trunk.
Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
→Use show vlan brief to verify access VLANs.
→Use show interfaces trunk to verify trunk state and allowed VLANs.
→Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
802.1X and TrustSec — This question tests 802.1X and TrustSec — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: It enables CTS inline tagging with a pre-shared key for SGT exchange between peers. — This enables CTS role-based enforcement globally and configures the interface for manual CTS with a pre-shared key (PMK) for SGT exchange. The 'mode-list both' allows both source and destination SGT enforcement.
What should I do if I get this 350-401 question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Consider this configuration for TrustSec on a Cisco switch:
cts role-based enforcement
interface GigabitEthernet1/0/5
cts manual
sap pmk AABBCCDDEEFF00112233445566778899 mode-list both
propagate sgt
What is the purpose of the 'propagate sgt' command under the interface?
medium
A.It allows the switch to receive SGT information from the connected device.
✓ B.It enables the switch to insert SGT tags into packets forwarded out of this interface.
C.It enables the switch to enforce role-based access control on this interface.
D.It configures the interface to use SXP for SGT propagation.
Why B: The 'propagate sgt' command enables the switch to insert SGT information into packets received on this interface, allowing SGT propagation to downstream devices.
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Question Discussion
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