CompTIA Updated N10-009 Exam Questions and Answers by haleema

A /21 subnet mask means 21 bits are network bits:

8 + 8 + 5 = 21 → leaves 11 bits for hosts.

Subnet mask in binary: 11111111.11111111.11111000.00000000

Converted to decimal: 255.255.248.0

Therefore:

A. /19 = 255.255.224.0

B. /20 = 255.255.240.0

✅ C. /21 = 255.255.248.0 ← correct

D. /22 = 255.255.252.0

Answer correction: The correct option is C. 255.255.248.0, not B.

References (CompTIA Network+ N10-009):

Domain: Networking Concepts — Subnetting, CIDR notation, dotted decimal masks.

VLAN hopping occurs when an attacker tricks a switch into believing the host is another switch by generating tagged frames or exploiting trunk negotiation (DTP). This allows the attacker to access traffic from multiple VLANs, potentially stealing sensitive data.

B. Evil twin is a rogue wireless AP attack, unrelated to switch impersonation.

C. DNS poisoning corrupts name resolution, not VLAN access.

D. ARP spoofing is a Layer 2 on-path attack, not masquerading as a switch.

References (CompTIA Network+ N10-009):

Domain: Network Security — VLAN hopping attacks, switch spoofing techniques.

Least privilege network access is a principle that restricts users' access rights to only what is necessary for them to perform their job functions. In this case, the accountant's access is limited to only the financial department's shared folders, ensuring that they cannot access other parts of the network unnecessarily. This reduces the risk of unauthorized access and potential data breaches. References: CompTIA Network+ Exam Objectives and official study guides.

Band Steering: This technology enables wireless devices to connect to the most optimal frequency band (2.4 GHz or 5 GHz) by encouraging capable devices to switch to the less congested 5 GHz band. This improves overall network performance and prevents overcrowding on the 2.4 GHz band.

Wireless LAN controller (B): This manages multiple access points in a network but does not handle frequency optimization.

Directional antenna (C): This focuses the signal in a specific direction but does not affect frequency selection.

Autonomous access point (D): This operates independently but lacks advanced features like band steering.