CompTIA Updated N10-009 Exam Questions and Answers by yusha

The correct answer is B. NAT64. This scenario says the internal network is using only IPv6. In the real world, many internet services still rely on IPv4, so an IPv6-only client may need a translation mechanism to reach IPv4-based servers. That is exactly where NAT64 is used. It allows communication between IPv6-only clients and IPv4 resources by translating between the two protocols.

The other options do not solve that requirement. MPLS is used for traffic forwarding across provider networks and has nothing to do with IPv4/IPv6 protocol translation. GRE creates tunnels, but it does not automatically translate one IP version into another. Static routing can direct traffic, but it cannot make IPv6-only hosts speak to IPv4-only internet destinations.

From a Network+ perspective, this question is testing knowledge of IPv6 transition and interoperability mechanisms. If the network is entirely IPv6 internally, but still needs access to parts of the internet that may be IPv4, some translation service has to exist at the boundary. Among the choices given, NAT64 is the only technology that fits that role. That is why B is the best answer.

This describes a Spanning Tree Protocol (STP) loop. If STP isn’t correctly configured or a redundant link is added without STP protection, it causes broadcast storms and network outages.

A. Unused ports disabled would not affect the entire network.

B. Missing default gateway on a switch doesn’t cause total network loss.

**C. Connecting a switch to an access port can cause VLAN mismatches, but not total connectivity loss unless a loop forms.

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CompTIA Network+ N10-009 Official Objectives: 3.6 – Explain the characteristics of network topologies and types.

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The correct answer is C. Address pool exhaustion. The laptop has assigned itself an address in the 169.254.x.x range, which is an APIPA address. That happens when the device is configured to use DHCP but cannot successfully obtain an address lease from a DHCP server. The missing default gateway and DHCP server entries support that conclusion.

Among the choices, the most likely reason is that the DHCP scope has run out of available addresses. When the pool is exhausted, new clients cannot receive a valid IP configuration and fall back to an automatic private address. As a result, the laptop will not be able to reach internal company resources like the intranet because it is not properly configured for the network.

The other answers do not fit the evidence. A short DHCP lease duration may cause more frequent renewals, but it does not directly explain the self-assigned APIPA address. An IIS server malfunction would affect the web service itself, not the client’s local IP configuration. An IDS misconfiguration also would not normally result in a 169.254 address on the host.

The output clearly indicates a DHCP assignment failure, and from the options provided, address pool exhaustion is the best match.

Quality of Service (QoS)is the best cost-effective solution. It prioritizes traffic based on application criticality. If the bandwidth is limited and only a few users are affected, prioritizing that application traffic can improve performance without needing costly bandwidth upgrades or direct connections.