CompTIA Network+ Question C-1

While troubleshooting, a technician notices that some clients using FTP still work and that pings to the local router and servers are working. The technician tries to ping all known nodes on the network and they reply positively, except for one of the servers. The technician notices that ping works only when the host name is used but not when FQDN is used. Which of the following servers is MOST likely down?

A. WINS server
B. Domain controller
C. DHCP server
D. DNS server

Correct Answer: D

CompTIA Network+ Question B-100

A technician is setting up a computer lab. Computers on the same subnet need to communicate with each other using peer to peer communication. Which of the following would the technician MOST likely configure?

A. Hardware firewall
B. Proxy server
C. Software firewall
D. GRE tunneling

Correct Answer: C

Explanation:
A host-based firewall is a computer running firewall software that can protect the computer itself. A software firewall would be the most cost effective in a lab scenario.

CompTIA Network+ Question B-99

A network technician has detected duplicate IP addresses on the network. After testing the behavior of rogue DHCP servers, the technician believes that the issue is related to an unauthorized home router. Which of the following should the technician do NEXT in the troubleshooting methodology?

A. Document the findings and action taken.
B. Establish a plan to locate the rogue DHCP server.
C. Remove the rogue DHCP server from the network.
D. Identify the root cause of the problem.

Correct Answer: B

Explanation:
By testing the behavior of rogue DHCP servers and determining that the issue is related to an unauthorized home router, the technician has completed the third step in the 7-step troubleshooting process. The next step is to establish a plan of action to resolve the problem and identify potential effects. Establishing a plan to locate the rogue DHCP server meets the requirements of this step.
1. Identify the problem. Information gathering. Identify symptoms. Question users.
Determine if anything has changed.
2. Establish a theory of probable cause. Question the obvious.
3. Test the theory to determine cause:
When the theory is confirmed, determine the next steps to resolve the problem. If theory is not confirmed, re-establish a new theory or escalate.
4. Establish a plan of action to resolve the problem and identify potential effects.
5. Implement the solution or escalate as necessary.
6. Verify full system functionality and if applicable implement preventive measures.
7. Document findings, actions, and outcomes.

CompTIA Network+ Question B-98

While troubleshooting a network outage, a technician finds a 100-meter fiber cable with a small service loop and suspects it might be the cause of the outage. Which of the following is MOST likely the issue?

A. Maximum cable length exceeded
B. Dirty connectors
C. RF interference caused by impedance mismatch
D. Bend radius exceeded

Correct Answer: D

Explanation:
The excessive bending of fiber-optic cables can increase microbending and macrobending losses. Microbending causes light attenuation induced by deformation of the fiber, while macrobending causes the leakage of light through the fiber cladding and this is more likely to happen where the fiber is excessively bent.

CompTIA Network+ Question B-97

A technician is setting up a new network and wants to create redundant paths through the network. Which of the following should be implemented to prevent performance degradation?

A. Port mirroring
B. Spanning tree
C. ARP inspection
D. VLAN

Correct Answer: B

Explanation:
The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of bridge loops, or the need for manual enabling/disabling of these backup links.

CompTIA Network+ Question B-96

An office network consists of one two-port router connected to a 12-port switch. A four-port hub is also connected to the switch. On this particular network, which of the following is the number of collision domain that exist?

A. 3
B. 12
C. 13
D. 14
E. 15

Correct Answer: D

CompTIA Network+ Question B-95

A technician needs to install software onto company laptops to protect local running services, from external threats. Which of the following should the technician install and configure on the laptops if the threat is network based?

A. A cloud-based antivirus system with a heuristic and signature based engine
B. A network based firewall which blocks all inbound communication
C. A host-based firewall which allows all outbound communication
D. A HIDS to inspect both inbound and outbound network communication

Correct Answer: C

Explanation:
A host-based firewall is a computer running firewall software that can protect the computer itself. For example, it can prevent incoming connections to the computer and allow outbound communication only.

CompTIA Network+ Question B-94

A technician is tasked with connecting a router to a DWDM. The technician connects the router to the multiplexer and confirms that there is a good signal level. However, the interface on the router will not come up. Which of the following is the MOST likely cause?

A. The wrong wavelength was demuxed from the multiplexer.
B. The SFP in the multiplexer is malfunctioning.
C. There is a dirty connector on the fiber optic cable.
D. The fiber optic cable is bent in the management tray.

Correct Answer: A

Explanation:
A multiplexer (or mux) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A demultiplexer (or demux) is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. Since the signal going in is good, the problem must be with the signal output. If the correct wavelength was demultiplexed, the interface will be displayed on the router.

CompTIA Network+ Question B-92

An attacker has connected to an unused VoIP phone port to gain unauthorized access to a network. This is an example of which of the following attacks?

A. Smurf attack
B. VLAN hopping
C. Bluesnarfing
D. Spear phishing

Correct Answer: B

Explanation:
The VoIP phone port can be used to attack a VLAN on the local network.
VLAN hopping is a computer security exploit, a method of attacking networked resources on a Virtual LAN (VLAN). The basic concept behind all VLAN hopping attacks is for an attacking host on a VLAN to gain access to traffic on other VLANs that would normally not be accessible.