Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A switchport is configured as an access port in VLAN 10, but a user plugs in a small unmanaged switch and connects multiple devices behind it. Which security feature most directly limits that behavior at the switchport?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Port security
This is correct because port security can limit MAC addresses learned on the port.
B
Distractor review
OSPF authentication
This is wrong because OSPF authentication is unrelated to switchport endpoint control.
C
Distractor review
NetFlow
This is wrong because NetFlow is for traffic-flow visibility, not direct access-layer limiting.
D
Distractor review
NTP
This is wrong because time synchronization does not limit endpoint behavior on a port.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that VLAN assignment alone restricts the number of devices behind a switchport. VLANs only segregate traffic logically and do not prevent multiple MAC addresses from appearing on a port. Another common mistake is selecting unrelated options like OSPF authentication, which secures routing protocol exchanges but does not control Layer 2 access. NetFlow and NTP are also unrelated to limiting connected devices. The key is recognizing that only port security directly limits how many MAC addresses can be learned on a port, thus controlling the number of connected devices.
Technical deep dive
How to think about this question
Port security is a Cisco switch feature that restricts the number of MAC addresses learned on a single switchport. It is designed to prevent unauthorized devices from connecting to the network by limiting the port to a predefined number of MAC addresses. When a port is configured as an access port in a specific VLAN, port security can enforce a limit on how many unique MAC addresses can be learned dynamically or statically on that port, effectively controlling endpoint access at Layer 2. The decision process for port security involves setting parameters such as the maximum number of MAC addresses allowed on the port, the violation mode (protect, restrict, or shutdown), and optionally specifying static MAC addresses. When a user connects an unmanaged switch behind the port, multiple MAC addresses appear on that single port. Port security detects this as a violation if the number of MAC addresses exceeds the configured limit, triggering the configured violation action to protect the network from unauthorized or unexpected devices. A common exam trap is confusing VLAN assignment with endpoint control. While VLANs segment traffic logically, they do not limit how many devices can connect behind a port. Features like OSPF authentication, NetFlow, or NTP are unrelated to controlling physical or MAC-level access on a switchport. Port security directly addresses this by monitoring MAC addresses, making it the correct and practical solution for limiting multiple devices behind a single access port.
KKey Concepts to Remember
- Port security restricts the number of MAC addresses learned on a switchport to control endpoint access at Layer 2.
- A switchport configured as an access port in a VLAN does not inherently limit how many devices can connect behind it.
- Port security violation modes determine the switch's response when the maximum allowed MAC addresses are exceeded on a port.
- VLAN assignment segments traffic but does not prevent multiple MAC addresses from appearing on a single switchport.
- OSPF authentication secures routing protocol exchanges and does not affect Layer 2 device access control on switchports.
- NetFlow provides traffic flow visibility and does not limit or control the number of devices connected to a switchport.
- NTP synchronizes time across devices and has no role in controlling switchport endpoint behavior or security.
- Port security can be configured with static or dynamic MAC addresses to enforce strict access control on switchports.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
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Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
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FAQ
Questions learners often ask
What does this 200-301 question test?
Port security restricts the number of MAC addresses learned on a switchport to control endpoint access at Layer 2.
What is the correct answer to this question?
The correct answer is: Port security — Port security most directly limits that behavior because it can restrict how many MAC addresses are learned on the switchport. In practical terms, if the interface is supposed to support one endpoint but suddenly begins presenting multiple MAC addresses from a downstream mini-switch, port security can detect and react to that change. This is a classic access-layer control question. VLAN assignment alone does not limit how many devices appear behind the port.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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