N10-009 Exam Dumps - CompTIA Network+ Certification Exam

When traffic moves laterally between VMs within the same network or subnet, it is known as east-west traffic. This contrasts with north-south traffic, which refers to communication between internal and external networks.

Breakdown of Options:

A. East-west – Correct answer. This refers to traffic between internal servers or VMs, which is a common security concern.

B. Point-to-point – Point-to-point describes a direct connection between two devices, but does not specifically define lateral movement.

C. Horizontal-scaling – This refers to adding more instances or nodes in cloud computing, unrelated to traffic flow.

D. Hub-and-spoke – This network topology describes a centralized design, not lateral traffic.

RADIUS (Remote Authentication Dial-In User Service) is a networking protocol that provides centralized Authentication, Authorization, and Accounting (AAA) management for users who connect and use a network service. RADIUS is often used to manage access to wireless networks, enabling users to authenticate with their company credentials, ensuring secure access to the network.References: CompTIA Network+ study materials. ​

OSPF is the most suitable routing protocol because it provides fast convergence and is commonly used as an interior gateway protocol within organizations. OSPF is a link-state routing protocol that builds a topology database and calculates the best path using cost. When a network change occurs, OSPF can converge much faster than older distance-vector protocols such as RIPv2. It is also widely supported by enterprise routing equipment and is appropriate for campus, school, and organizational networks.

The CompTIA Network+ N10-009 objectives include routing technologies, dynamic routing protocols, administrative distance, convergence, and routing protocol selection. OSPF is often preferred in internal networks because it scales better than RIP and can be configured in a single area for relatively simple deployments, reducing configuration complexity.

IS-IS is also a link-state protocol and can converge quickly, but it is less commonly used in typical small or medium enterprise environments and may require more specialized knowledge. RIPv2 has simpler configuration but slower convergence and hop-count limitations. BGP is mainly used for external routing between autonomous systems and is not the best choice for an internal school network. Therefore, OSPF is correct.

A client-to-site VPN (remote-access VPN) is designed to let an individual user securely connect into an organization’s network over an untrusted network (like the internet) and access resources as if the user were locally connected. Network+ objectives emphasize VPNs as encrypted tunnels that provide confidentiality and integrity for traffic, commonly using technologies such as IPsec or SSL/TLS-based VPNs. With a client-to-site VPN, the user’s device establishes a tunnel to the corporate VPN gateway, receives routes (and sometimes DNS settings), and can reach internal subnets and cloud resources according to policy.

A jump box/host is a hardened intermediate system used to access sensitive segments, but it does not make the user’s device behave as if it is directly on the network; it provides controlled administrative access. SSH is a secure remote management protocol for connecting to a host’s command line—useful for administration, not full network access to multiple internal resources. A GRE tunnel provides encapsulation but does not provide encryption by itself, so it is not inherently “securely access” unless combined with additional security (e.g., GRE over IPsec). Therefore, client-to-site VPN is the correct choice.

Fiber connections require Tx on one end to connect to Rx on the other end. If the patch cord is replaced and link lights remain off, the most common cause is that the connectors are reversed. Swapping (transposing) the connectors ensures proper transmit/receive alignment.

A. Replacing the transceiver may eventually be necessary, but only after verifying correct connections.

B. Restarting the switchport won’t resolve a physical misconnection.

D. Using multimode fiber would be incorrect here, as the link was designed for single-mode (10 miles/16 km requires SMF).

References (CompTIA Network+ N10-009):

Domain: Network Troubleshooting — Fiber connectivity, Tx/Rx alignment, link light diagnostics.

Comprehensive and Detailed Explanation (aligned to N10-009):

Multimode fiber uses multiple paths (modes) of light that bounce off the cladding to travel through the fiber. This is effective for shorter distances but more prone to dispersion.

A. Twinaxial is copper, not fiber.

B. Coaxial carries electrical signals, not light.

C. Single-mode fiber uses a single light path directly through the core without bouncing.

References (CompTIA Network+ N10-009):

Domain: Networking Concepts — Fiber optics: single-mode vs. multimode.

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: Create 3 subnets, each with 30 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 least 3 subnets.

At least 32 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 bits for 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 provides exactly 30 usable hosts per subnet, avoiding waste while meeting the minimum requirement.

It allows 8 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.

Understanding the 169.254.x.x Address:

An IPv4 address in the range of 169.254.x.x is an Automatic Private IP Addressing (APIPA) address, assigned when a DHCP server is unavailable.

DHCP Server Offline:

APIPA Assignment: When a device cannot obtain an IP address from a DHCP server, it assigns itself an APIPA address to enable local network communication. This allows communication with other devices on the same local subnet but not with external networks.

Resolution: Ensure the DHCP server is operational. Check for connectivity issues between the virtual machine and the DHCP server, and verify the DHCP server settings.

Comparison with Other Options:

The subnet mask is incorrect: The subnet mask 255.255.0.0 is appropriate for the 169.254.x.x range and does not prevent external access by itself.

The IP address is an RFC1918 private address: RFC1918 addresses are private IP ranges (10.x.x.x, 172.16.x.x-172.31.x.x, 192.168.x.x) but 169.254.x.x is not one of them.

The DNS server is unreachable: While this could affect name resolution, it would not prevent the assignment of a non-APIPA address or local network communication.

Troubleshooting Steps:

Verify the DHCP server’s status and connectivity.

Restart the DHCP service if necessary.

Renew the IP lease on the virtual machine using commands such as ipconfig /renew (Windows) or dhclient (Linux).