Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A network administrator notices that several workstations on the network are receiving IP addresses from an unknown source, causing intermittent connectivity issues. The DHCP server is located in the server room and is the only authorized DHCP server. Which security feature should be implemented on the access switches to prevent rogue DHCP servers from distributing IP addresses?
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
DHCP Snooping
DHCP Snooping filters DHCP messages and only allows DHCP offers from trusted ports, blocking rogue DHCP servers.
B
Distractor review
Dynamic ARP Inspection
DAI validates ARP packets to prevent ARP spoofing, not DHCP-related attacks.
C
Distractor review
IP Source Guard
IP Source Guard prevents IP spoofing by verifying source IP addresses against DHCP snooping bindings, but does not block rogue DHCP servers.
D
Distractor review
Port Security
Port Security restricts the number of MAC addresses per port, but does not prevent unauthorized DHCP servers.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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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 network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?
Question 2
A network engineer is designing a new switched network and needs to ensure that broadcast traffic from one department does not reach another department's workstations. The engineer plans to use VLANs. Which of the following must be configured on the switches to isolate broadcast domains as intended?
Question 3
A security engineer is configuring a site-to-site VPN between two branch offices. The requirement is to encrypt all traffic between the two networks using IPsec. Which IPsec mode should be used to encrypt the entire IP packet including the original header?
Question 4
A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
Question 5
A network administrator is experiencing issues where unauthorized devices are offering IP addresses to clients, causing connectivity problems. Which security feature should be enabled on switches to prevent this?
Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: DHCP Snooping — DHCP Snooping is a security feature that filters DHCP messages and validates that DHCP offers originate only from trusted ports (typically ports connected to the legitimate DHCP server). It drops DHCP offers from untrusted ports, preventing rogue DHCP servers from assigning IP addresses. Dynamic ARP Inspection (DAI) mitigates ARP spoofing, IP Source Guard prevents IP spoofing, and Port Security limits the number of MAC addresses per port, but none address rogue DHCP servers directly.
What should I do if I get this N10-009 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
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