This 200-301 practice question tests your understanding of network services and security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: dHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network.. 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.
Which feature helps prevent a rogue DHCP server from handing out addresses on a campus switch network?
PortFast
Why wrong: PortFast speeds edge-port transitions but does not validate DHCP sources.
DHCP snooping
Correct. DHCP snooping is designed for this threat.
HSRP
Why wrong: HSRP provides gateway redundancy, not rogue DHCP protection.
LLDP
Why wrong: LLDP is a discovery protocol and not a DHCP security control.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
DHCP snooping
DHCP snooping classifies interfaces as trusted or untrusted and can block unauthorized DHCP server replies arriving on untrusted ports.
Key principle: DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
PortFast
When this WOULD be correct
In a different exam scenario, a question might ask about features that optimize switch port behavior for end devices in a network where rapid connectivity is crucial. In that case, a question could ask about improving the speed of port activation for devices like VoIP phones, making PortFast the correct answer.
DHCP snooping
Why this is correct
Correct. DHCP snooping is designed for this threat.
Related concept
DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network.
HSRP
LLDP
Why it's wrong here
LLDP is a discovery protocol and not a DHCP security control.
When this WOULD be correct
If the exam question asked about protocols that enhance network management and device discovery, LLDP would be the correct answer. For example, a question could focus on how to identify and manage devices on a switch network, where LLDP plays a crucial role.
Option-by-option analysis
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.
Why this is correct
Correct. DHCP snooping is designed for this threat.
Why this is wrong here
PortFast is a Spanning Tree Protocol feature that immediately transitions an access port to the forwarding state, bypassing the listening and learning states. It does not inspect or validate DHCP messages, so it cannot prevent a rogue DHCP server from handing out addresses.
★ When this WOULD be the correct answer
In a different exam scenario, a question might ask about features that optimize switch port behavior for end devices in a network where rapid connectivity is crucial. In that case, a question could ask about improving the speed of port activation for devices like VoIP phones, making PortFast the correct answer.
Why candidates choose this
Students might think PortFast provides security because it is often used on edge ports where end devices connect, and they may confuse its rapid transition with a security feature that blocks unauthorized servers.
Why this is wrong here
HSRP (Hot Standby Router Protocol) provides first-hop redundancy by allowing multiple routers to share a virtual IP address, ensuring gateway availability. It does not inspect DHCP traffic or provide any mechanism to block unauthorized DHCP servers.
★ When this WOULD be the correct answer
If the exam question asked about ensuring high availability and redundancy for gateway devices in a network, HSRP would be the correct answer, as it allows multiple routers to work together to present a single virtual IP address to clients.
Why candidates choose this
Because HSRP involves IP address management and redundancy, some students might mistakenly believe it can also manage or secure DHCP address assignment, especially since both operate at Layer 3.
Why this is wrong here
LLDP (Link Layer Discovery Protocol) is a vendor-neutral protocol used for discovering neighboring devices and their capabilities by exchanging information such as device type, management addresses, and VLAN IDs. It has no role in DHCP security or filtering DHCP messages.
★ When this WOULD be the correct answer
If the exam question asked about protocols that enhance network management and device discovery, LLDP would be the correct answer. For example, a question could focus on how to identify and manage devices on a switch network, where LLDP plays a crucial role.
Why candidates choose this
LLDP is a Layer 2 protocol that operates on switches, and students might confuse it with DHCP snooping because both are associated with network discovery and management, but they serve entirely different purposes.
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?”
Common exam traps
Avoid confusing PortFast (which skips STP convergence) with DHCP-specific features like DHCP Snooping.
Detailed technical explanation
DHCP snooping is a security feature implemented on Cisco switches to protect the network from rogue DHCP servers. It works by monitoring DHCP messages exchanged between clients and servers and classifying switch ports as trusted or untrusted. Trusted ports are those connected to legitimate DHCP servers, while untrusted ports are typically edge ports connected to clients. DHCP snooping filters DHCP server responses on untrusted ports, blocking any unauthorized DHCP offers or acknowledgments that could assign incorrect IP addresses. When DHCP snooping is enabled, the switch builds a DHCP binding table that records client MAC addresses, IP addresses, lease times, and associated ports. This table helps the switch enforce IP address assignment policies and supports other security features like IP source guard and dynamic ARP inspection. The decision process involves trusting DHCP server messages only from ports explicitly configured as trusted, thereby preventing rogue DHCP servers from handing out addresses on the network. A common exam trap is confusing DHCP snooping with other features like PortFast or HSRP. PortFast accelerates spanning-tree port transitions but does not provide DHCP security. HSRP offers gateway redundancy but does not control DHCP traffic. LLDP is a discovery protocol unrelated to DHCP security. Practically, enabling DHCP snooping is essential in campus networks to maintain IP address integrity and prevent attackers from disrupting network connectivity by introducing rogue DHCP servers.
Key takeaway
DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network.
Real-world example
A practitioner preparing for the 200-301 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Review dHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network., then practise related 200-301 questions on the same topic to reinforce the concept.
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FAQ
Network Services and Security — This question tests Network Services and Security — DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network..
The correct answer is: DHCP snooping — DHCP snooping classifies interfaces as trusted or untrusted and can block unauthorized DHCP server replies arriving on untrusted ports.
Review dHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network., then practise related 200-301 questions on the same topic to reinforce the concept.
DHCP snooping classifies switch ports as trusted or untrusted to control which devices can send DHCP server messages on a network.
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Last reviewed: May 17, 2026
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