N10-009 Exam Results

The correct answer is D. DHCP reservation. In a network environment, printers are typically configured to use a consistent IP address so that client devices can reliably locate them. After a power outage, network devices such as printers may reboot and request a new IP address from the DHCP server. If the printer was previously assigned a dynamic IP address, it may now receive a different address, causing users’ systems to lose connectivity because they are still trying to print to the old IP.

A DHCP reservation ensures that a specific device (identified by its MAC address) always receives the same IP address from the DHCP server. This combines the convenience of DHCP with the stability of static addressing, which is ideal for shared resources like printers.

The other options are incorrect for this scenario. DoH (DNS over HTTPS) secures DNS queries and is unrelated to IP address assignment. SLAAC (Stateless Address Autoconfiguration) is used for IPv6, not IPv4 environments. APIPA (Automatic Private IP Addressing) assigns a link-local address when DHCP fails, but it does not provide consistent or routable addressing suitable for shared printers.

Therefore, configuring a DHCP reservation ensures consistent network access to the printer after power disruptions.

A jump box is a hardened system that provides secure access to isolated or sensitive devices on a separate network.

Breakdown of Options:

A. Jump box – ✅ Correct answer. Acts as a middle point for secure remote access.

B. API gateway – Used for managing API calls, not remote access to isolated devices.

C. Secure Shell (SSH) – Requires direct connectivity, which may not be available for an isolated device.

D. Clientless VPN – Allows web-based VPN access, but does not guarantee access to isolated devices.

When a DHCP server is installed and not enough IP addresses are provisioned, users may start experiencing network outages once the available IP addresses are exhausted. DHCP servers assign IP addresses to devices on the network, and if the pool of addresses is too small, new devices or those renewing their lease may fail to obtain an IP address, resulting in network connectivity issues.References: CompTIA Network+ study materials.

If the business shares or duplicates the ISP-assigned public IP address, routing instability and conflicts will occur. Pinging a public IP like 8.8.8.8 may work (since ICMP can bypass certain conflicts), but browsing websites (which requires stable sessions and return traffic) will fail intermittently.

A. If the default gateway were incorrect, no external connectivity would work at all.

B. VLAN mismatch is an internal issue, not affecting ISP routing.

C. Subnet mask misconfiguration would prevent consistent routing but usually blocks ping too.

References (CompTIA Network+ N10-009):

Domain: Network Troubleshooting — Internet connectivity issues, ISP IP conflicts.