CompTIA Network+ N10-009 Dumps PDF

Comprehensive and Detailed Explanation:

VLANs (Virtual Local Area Networks)segment network trafficby department, allowingACLs (Access Control Lists)to be appliedbased on VLAN membership, improving security and resource isolation.

Breakdown of Options:

A. VLAN–Correct answer.VLANs enablelogical network segmentation, allowingACLs per department.

B. DHCP– Assigns IP addresses butdoes not control access.

C. VPN– Providesremote access,not segmentation within a network.

D. STP– Preventsswitching loops,not related to ACL implementation.

A Change Advisory Board (CAB) reviews and approves network changes. Before approval, they need a detailed action plan outlining the change, potential impacts, and mitigation strategies.

A Plan of Action includes risk assessments, rollback procedures, and deployment steps, which are critical for decision-making.

? Reference: CompTIA Network+ (N10-009) Official Study Guide – Section: Network Troubleshooting Methodologies

Anevil twinis arogue Wi-Fi access pointthat mimics a legitimate network. Attackers use it tointercept and manipulate traffic, making it anon-path (formerly MITM) attackopportunity.

Breakdown of Options:

A. Phishing– Tries tosteal credentialsthrough fake emails/websites but doesnot intercept network traffic.

B. Dumpster diving– Involvesphysical security breaches,not network interception.

C. Evil twin–✅Correct answer.A rogueWi-Fi AP impersonates a real network, allowingtraffic interception.

D. Tailgating– Involvesphysical access security,not network interception.

Understanding the Requirements

Network Address: 192.168.1.0/24

The /24 notation means a subnet mask of 255.255.255.0, providing 256 total addresses (192.168.1.0–192.168.1.255).

Usable hosts: 256 – 2 (network and broadcast) = 254.

Goal: Create3 subnets, each with30 hosts.

Each subnet needs enough addresses to accommodate 30 hosts, plus 2 reserved addresses (network and broadcast) per subnet.

Total addresses per subnet = 30 (hosts) + 2 (network/broadcast) =32 addresses.

Subnetting Basics (Networking Fundamentals)

Subnet Mask: Determines how many bits are borrowed from the host portion to create subnets.

Original Mask: /24 (255.255.255.0) = 24 network bits, 8 host bits.

Formulae:

Number of subnets = 2^(number of borrowed bits).

Number of addresses per subnet = 2^(remaining host bits).

Usable hosts per subnet = 2^(remaining host bits) – 2.

We need:

At least3 subnets.

At least32 addresses per subnet(to fit 30 hosts + 2 reserved).

Step-by-Step Analysis

Determine Addresses Needed per Subnet:

32 addresses is a power of 2 (2^5 = 32).

This means each subnet requires 5 host bits (since 2^5 = 32 total addresses, and 32 – 2 = 30 usable hosts).

Calculate Remaining Bits:

Original network has 8 host bits (/24).

If 5 bits are left for hosts, we borrow: 8 – 5 =3 bitsfor subnetting.

New Subnet Mask:

Original mask: /24 (24 network bits).

Borrow 3 bits: 24 + 3 =/27.

/27 = 255.255.255.224 (binary: 11111111.11111111.11111111.11100000).

Verify Requirements:

Number of Subnets: 2^3 =8 subnets(meets the requirement of at least 3).

Addresses per Subnet: 2^5 =32 addresses.

Usable Hosts per Subnet: 32 – 2 =30 hosts(exactly meets the requirement).

Subnet Breakdown:

Increment: 256 – 224 =32(each subnet increments by 32 in the fourth octet).

Subnets:

192.168.1.0–192.168.1.31 (Network: .0, Broadcast: .31, Hosts: .1–.30)

192.168.1.32–192.168.1.63 (Network: .32, Broadcast: .63, Hosts: .33–.62)

192.168.1.64–192.168.1.95 (Network: .64, Broadcast: .95, Hosts: .65–.94)

(And 5 more subnets up to 192.168.1.255.)

Three subnets fit perfectly with 30 hosts each.

Evaluating the Options

A. 255.255.255.128 (/25):

Borrow 1 bit: 24 + 1 = /25.

Subnets: 2^1 = 2 (not enough, need 3).

Host bits: 7 (2^7 = 128 addresses, 126 hosts).

Why Not: Only 2 subnets, fails the requirement.

B. 255.255.255.192 (/26):

Borrow 2 bits: 24 + 2 = /26.

Subnets: 2^2 = 4 (meets 3).

Host bits: 6 (2^6 = 64 addresses, 62 hosts).

Why Not: 62 hosts exceeds 30, but it’s overkill; /27 is more efficient and still valid.

C. 255.255.255.224 (/27):

Borrow 3 bits: 24 + 3 = /27.

Subnets: 2^3 = 8 (meets 3).

Host bits: 5 (2^5 = 32 addresses, 30 hosts).

Why Yes: Perfectly fits 3 subnets with exactly 30 hosts each.

D. 255.255.255.240 (/28):

Borrow 4 bits: 24 + 4 = /28.

Subnets: 2^4 = 16 (meets 3).

Host bits: 4 (2^4 = 16 addresses, 14 hosts).

Why Not: Only 14 hosts per subnet, fails the 30-host requirement.

Why /27 (255.255.255.224) is Best

It providesexactly 30 usable hosts per subnet, avoiding waste while meeting the minimum requirement.

It allows8 subnets, exceeding the need for 3, ensuring flexibility.

The study guide emphasizes efficient subnet design, and /27 balances host count and subnet availability.

CompTIA Network+ Context

Networking Fundamentals: Subnetting is a core skill, requiring understanding of CIDR, binary conversion, and address allocation.

Example from Study Guide: Similar problems calculate subnet masks for specific host counts, reinforcing /27 as a common solution for ~30 hosts.