- (Topic 4)
Which of the following explains how using a cloud infrastructure can provide rapid elasticity?

1. A. Shared resources can reduce overhead.
2. B. Customers can limit the use of a resource
3. C. High availability of services can be provided
4. D. Systems can be provisioned according to demand.

Correct Answer: D
Systems can be provisioned according to demand. This is the essence of rapid elasticity, which is one of the essential characteristics of cloud computing. Rapid elasticity means that cloud services can be scaled up or down quickly and automatically, depending on the changing needs of the customers. This provides flexibility, efficiency, and cost- effectiveness for both the customers and the providers. According to the CompTIA Core1 objectives, one of the benefits of cloud computing is rapid elasticity. A research paper on cloud elasticity also defines it as the ability to dynamically adjust the amount of resources allocated to a service in response to its workload variation.

- (Topic 4)
A technician attempts to join a Windows client to a domain but receives the following error: An attempt to resolve the hostname has failed.
The technician generates the display shown below utilizing ipconfig /all.

Which of the following is the most likely reason for the error?

1. A. DNS
2. B. Physical address
3. C. Subnet mask
4. D. IPv4 address
5. E. Default gateway

Correct Answer: A
The most likely reason for the error is that the DNS server is not configured correctly. The technician should check the DNS server settings and make sure they are correct.
DNS, or Domain Name System, is a service that translates domain names, such as www.example.com, into IP addresses, such as 192.168.1.1, that computers use to communicate with each other. DNS is essential for joining a Windows client to a domain, which is a logical group of computers that share a common directory and security policy. A domain name, such as example.com, identifies the domain and its members on the network.
To join a Windows client to a domain, the client needs to resolve the hostname of the domain controller, which is the server that manages the domain and its resources. The client sends a DNS query to the DNS server, asking for the IP address of the domain controller. The DNS server responds with the IP address, and the client uses it to establish a connection with the domain controller and complete the domain join process.
However, if the DNS server is not configured correctly, the client may not be able to resolve the hostname of the domain controller, and receive the error: An attempt to resolve the hostname has failed. This can happen if the DNS server is not reachable, not authoritative, or not updated. For example, the DNS server may have an incorrect IP address, a wrong DNS suffix, a missing or outdated DNS record, or a firewall blocking the DNS traffic.
To fix the error, the technician should verify that the DNS server settings on the client and the domain controller are correct and consistent. The technician can use the ipconfig /all command to display the DNS server settings, such as the IPv4 address, the subnet mask, the default gateway, and the DNS suffix. The technician can also use the nslookup command to test the DNS resolution and the ping command to test the connectivity. The technician should make sure that the client and the domain controller are using the same DNS server, and that the DNS server can resolve the hostname of the domain controller. References:
✑ How to Resolve the "Temporary failure in name resolution" Error1
✑ Strict hostname resolution configured but no hostname was set2
✑ Error: Hostname Not Resolved to an IP Address - HostGator3
✑ The Host Name Could Not be Resolved in DNS4
✑ Troubleshoot DNS name resolution on the Internet - Windows Server5

- (Topic 3)
A technician connects a new computer to the internet and then opens the wiring closet. Even though all of the wires are terminated, nothing in the wring closet is labeled. Which of the following tools should the technician use to complete the task?

1. A. Cable tester
2. B. Loopback plug
3. C. Toner probe
4. D. Punchdown tool

Correct Answer: C
A toner probe is a tool that can be used to trace and identify cables in a wiring closet. The technician can use a toner probe to find the cable that connects the new computer to the internet. A cable tester is a tool that can be used to check the continuity and quality of a cable. A loopback plug is a tool that can be used to test network ports or cables by sending and receiving signals from the same device. A punchdown tool is a tool that can be used to terminate wires into a patch panel or jack.

- (Topic 2)
A technician set up a new access point and has noticed significant latency on the selected channel. Which of the following tools can assist with locating the BEST channel to use?

1. A. Wi-Fi analyzer
2. B. Netstat
3. C. Net use
4. D. Traceroute
5. E. Network tap

Correct Answer: A
A Wi-Fi analyzer is a tool that can be used to scan the local area for available wireless networks and can provide information such as signal strength, interference, and available channels. It can also be used to locate the best channel to use for a given access point, which can help to reduce latency and improve performance.

- (Topic 1)
A Wi-Fi mesh network has been optimized to eliminate poor coverage areas, yet users still experience decreased bandwidth and connectivity issues. Which of the following actions should the technician take NEXT?

1. A. Relocate any large, dense, solid, and metal objects, such as mirrors and file cabinets, in the mesh network coverage area to the perimeter so that wireless reflections, absorptions, and occlusions are minimized.
2. B. Use a Wi-Fi analyzer to determine whether the channel in use is overcrowded and to identify which channel the mesh network should use for best performance.
3. C. Use the signal strength indicator on a mobile device to roam the coverage area and generate a heat map to isolate zones with weak signals.
4. D. Turn off broadcasting of the SSID on the mesh network so that other networks cannot see it.

Correct Answer: B
If users are experiencing decreased bandwidth and connectivity issues in a Wi-Fi mesh network, the technician should use a Wi-Fi analyzer to determine whether the channel in use is overcrowded and to identify which channel the mesh network should use for best performance. References: CompTIA A+ Certification Study Guide, Tenth Edition, pg. 308