Module 8: Network Infrastructure and Troubleshooting

Question 1

Which of the following are valid IPv4 private IP addresses? (Select TWO.)

Answer 1

10. 20.30.40
11. 29.29.254

This is a valid IPv4 private IP address in the range of 10.0.0.0–10.255.255.255.

This is a valid IPv4 private IP address in the range of 172.16.0.0–172.31.255.255.

Question 2

What is the purpose for the twists in twisted pair Ethernet cabling?

Answer 2

Reduce crosstalk between wire pairs.

The twists in a twisted pair cable reduce crosstalk between pairs. Crosstalk is interference induced by a wire that interferes with neighboring wires.

Question 3

Consider the following configuration.
​

Computer “A”

              IP address:          172.16.100.100

              Subnet mask:     255.255.0.0

​

Computer “B”

              IP address:          172.16.200.200

              Subnet mask:     /16

What should be done to allow these computers to send and receive data to and from each other?

Answer 3

Nothing needs to be changed.

Start by comparing the two assigned subnet masks, and you determine that the two computers are using the same subnet mask (255.255.0.0 and /16). Next, compare the network ID for each computer, and you can see they are both on the same network (172.16.0.0). Now, verify that both computers are using valid host addresses (0.0.100.100 and 0.0.200.200). These two computers will communicate with no changes.

Question 4

A technician is troubleshooting a small network with cable Internet service in which a user is receiving a message in her web browser stating a site cannot be found. While interviewing users, it is determined that every host on the network is experiencing the same issue with all websites.

Which of the following is the first step in troubleshooting this issue?

Answer 4

Connect a computer directly to the cable modem and attempt to access the Internet.

The first step is to eliminate all devices except the cable modem and ISP connection. Connecting a PC directly to the RJ-45 port on the cable modem eliminates all other devices. An alternative first step could be to reboot the cable modem and reattempt Internet access.

Question 5

The accounting department moved its network-attached printer from one side of the office to a more centralized location, making the printer much more accessible to all accounting users. Since the move, the users have not been able to print to the printer. The printer powers on and shows it is ready to accept print jobs. The printer configuration page shows the following output.

You disconnect the patch cable from the keystone jack at the new location and move the printer and cable to reconnect it at the original location. The printer begins printing the jobs that failed to print earlier.

Which of the following are the most likely reasons for the printer failing to print at the new location? (Select TWO.)

Answer 5

The cable run connecting the new keystone jack to the patch panel is bad.

The patch panel connector for the new location’s cable run is not connected to a switch.

The printer is set for DHCP configuration and is assigning itself APIPA parameters at the new location. Because the printer will function properly at the original location, the printer does not have layer 1 network connectivity at the new location. There is an issue with the keystone jack, cable run, patch panel, patch cable at the patch panel, or switch.

The printer is set for DHCP configuration and is assigning itself APIPA parameters at the new location. Because the printer will function properly at the original location, the printer does not have layer 1 network connectivity at the new location. There is an issue with the keystone jack, cable run, patch panel, patch cable at the patch panel, or switch.

Question 6

A coworker is asking for your advice on a problem with a computer that will not communicate on the network. While assisting the coworker, you suspect that the wired NIC may have failed.

Which of the following will you recommend to your coworker as the best tool to diagnose this issue? (Select TWO.)

Answer 6

Loopback plug
Network multimeter

A loopback plug is used to reroute a network port’s output signal back to the same port’s input pins. Performing a loopback test will verify whether the port on the NIC is functioning.

An electrical multimeter is used to test for voltage, amperage, resistance, and continuity. A network multimeter is used to test cables, ports, and network adapters. When you connect a network multimeter to your network, it can also detect the Ethernet speed, duplex status, default router on the network, lengths of cables, voltage levels of PoE, and other network statistics and details.

Question 7

Your company is experiencing an increase in malware incidents. Your manager is asking for advice on how best to verify that company-owned workstations are up-to-date with security patches, anti-malware requirements, and software application updates. The manager is also concerned that employee-owned devices connecting to the corporate LAN have the same level of security as the company devices.

Which of the following protections and services should you recommend?

Answer 7

Implement an endpoint management server appliance.

An endpoint management server will monitor endpoint devices on the network to ensure they meet the most current security requirements. If security requirements are met, the device is granted access to the network. The user or device will still be required to authenticate on the network. If the endpoint management server determines a device does not meet the minimum security requirements, the device’s access to the network is blocked.

Question 8

A technician is working at a client’s office after hours and needs two cables to finish the work but does not have immediate access to prebuilt cables. One cable needed is for a dial-up connection from the dial-up modem to the existing analog POTS jack on the wall. The other cable is for an Ethernet connection from the computer to the existing keystone jack on the wall. The technician has the necessary wire and connectors to make the cables.

Which of the following tools will the technician use to make the cables and then verify that they both work properly? (Select THREE.)

Answer 8

Crimper
Cable tester
Cable stripper

A crimper tool is used to attach connectors onto the ends of a cable. The crimper must be compatible with the crimp (or connector). Common network and telephone connectors that are attached using a crimper are RJ-45, RJ-11, F-type, and BNC. This question will require RJ-11 crimps as well as RJ-45 crimps.

A cable tester is used to determine whether a cable is good. A good cable is wired correctly (based on the type of cable desired) and provides a complete circuit from end to end for all wires. This question will require the use of a cable tester after each cable is made.

A cable stripper is used to remove the outer sheath from a cable, thus exposing the individual wires or conductors. A cable stripper will be required for this scenario for both cables.

Question 9

A new Cat6 cable run and keystone jack were installed for a workstation that was moved from the sales department to the shipping department. Since the move, the user has been complaining of slow transfer speeds on both Internet and local network communications. The technician ran a test and is viewing the following output on the tester.

Which of the following is the most likely reason for the sluggish network speeds?

Answer 9

The cable run exceeds the specifications for Ethernet over twisted pair.

The workstation was functioning properly prior to the move, indicating the problem is related to the move. The cable run is the only change made.

Question 10

Examine the exhibit above.

Which network tool most likely produced the output?

Answer 10

Network multimeter

An electrical multimeter is used to test for voltage, amperage, resistance, and continuity. A network multimeter is used to test cables, ports, and network adapters. When you connect a network multimeter to your network, it can also detect the Ethernet speed, duplex status, default router on the network, lengths of cables, voltage levels of PoE, and other network statistics and details.

Question 11

Which of the following are secure protocols, ports, services, or applications? (Select TWO.)

Answer 11

Port 443
SSH

Port 443 is used for secure HTTP (Hypertext Transfer Protocol) web transmissions. HTTPS refers to HTTP working with a security protocol such as SSL (Secure Sockets Layer) or TLS (Transport Layer Security).

SSH (Secure Shell) protocol is assigned port 22 and is used in various situations for encryption, making SSH secure. One application for SSH is as a secure alternative for Telnet.

Question 12

Examine the exhibit above.

Host B is sending an email intended for the user on Host A to the email server. What protocol is being used to send the message through the router?

Answer 12

SMTP

SMTP (Simple Mail Transfer Protocol) is used to send email to its destination. The email server listens on port 25 to receive email from a client. An email server using secure SMTPS listens on port 465 and utilizes SSL/TLS (Secure Sockets Layer/Transport Layer Security).

Question 13

A technician wants to consolidate and log specific alerts from network devices into a database so maintenance tasks and potential device problems can be addressed in a timely manner.

Which of the following should the technician implement?

Answer 13

Syslog server

A Syslog server collects events, such as errors, failures, maintenance tasks, and security events, from network-connected devices and organizes these events into a database for sorting and viewing. Many Syslog servers can also be used to notify network administrators of problems that may require their attention.

Question 14

You replaced the LCD panel in a laptop computer and verified full system functionality, including wireless connectivity. The customer picked up the laptop and now reports he can no longer access his wireless network regardless of how close the computer is positioned to the WAP. Other users can connect to the WAP without any problem.

Which of the following is the most likely reason for this problem?

Answer 14

The laptop’s wireless radio is toggled to the off position.

Laptop computers and mobile devices provide a method of turning off the wireless network and Bluetooth radios independently of each other. Many devices also have an airplane mode in which all radios can be turned off simultaneously. This is the most likely reason for the problem given that the laptop wireless was tested and the other users on the client’s WLAN are functioning properly.

Question 15

Which of the following is a function of an endpoint management server appliance?

Answer 15

Restricting a device’s access to the network until security requirements are met.

An endpoint management server will monitor endpoint devices on the network to ensure they meet the most current security requirements. If security requirements are met, the device is granted access to the network. The user or device will still be required to authenticate on the network. If the endpoint management server determines a device does not meet the minimum security requirements, the device’s access to the network is blocked.

Question 16

Which of the following indicates the most concise abbreviation of the IPv6 address FEFE:0000:0000:0000:0002:0000:0000:0001?

Answer 16

FEFE::2:0:0:1

This is the most concise abbreviation of the example IP address.

Question 17

Which of the following describes an IPv6 link -local address assigned to a node on a network?

Answer 17

A private unicast address used for limited communication with neighboring nodes in the same link.

This answer describes a link- local unicast address. These addresses are similar to IPv4 APIPA addresses, which the computer assigns to itself. Most link- local addresses begin with FE80::/64 and are not routable (allowed) on the public Internet.

Question 18

What methods are used to assign TCP/IP parameters to network hosts? (Select TWO.)

Answer 18

Dynamic
Static

DHCP (Dynamic Host Configuration Protocol) is the protocol used to automatically (or dynamically) assign TCP/IP parameters to a host. A DHCP server must be configured on the same network as the host, and the host must be configured to obtain an IP address automatically.

Manually configured TCP/IP parameters are statically assigned and do not change unless explicitly configured by a technician or user. Typical hosts that utilize static assignment are printers, servers, and other devices where the IP address must remain constant.

Question 19

A Windows user has been successfully saving documents to the file server all morning. However, the latest attempt resulted in the following message, “Could not find this item. Verify the location of ‘\FileServer\Docs’ and try again.”

Which of the following is the most likely cause for this message?

Answer 19

The share to the file server is disconnected.

The most likely reason for this error is that the share is currently not available either on just the user’s computer or server-wide. The next step would be to check for the scope of the problem.

Question 20

A company requires an Ethernet connection from the north end of its office building to the south end. The distance between connections is 161 meters and will need to provide speeds of up to 10 Gbps in full duplex mode.

Which of the following cable combinations will meet these requirements?

Answer 20

Multimode fiber cable with MT-RJ connectors

Multimode fiber is the best option for 10 Gbps speeds at distances over 100 meters.

Question 21

While assisting a Windows user over the phone, you need to determine the IP address for the DHCP server along with the MAC address of the Ethernet NIC. The user has successfully opened a command prompt.

What command will you have the user type at the command line to determine these two addresses?

Answer 21

ipconfig /all

The ipconfig command will display IP configuration information such as IPv4 and IPv6 addresses, subnet masks, and default gateways for your installed network interface controllers. Appending the “/all” switch to the command gives much more information for each NIC, including the MAC address, the DHCP server, and the DNS servers.

Question 22

You are using a crimper to attach an RJ-45 connector to a Cat 6 UTP cable. Your company requires that all cabling follow the TIA/EIA 568B standard.

Which wire color code will you use starting with pin 1 of the modular plug?

Answer 22

Orange/white, orange, green/white, blue, blue/white, green, brown/white, brown

This is the correct color code for the T568B standard starting with pin 1.

Question 23

In which of the following situations should you install an IPS instead of an IDS?

Answer 23

ou want to block unauthorized activity on your LAN from the Internet.

An intrusion prevention system will monitor, detect, log, issue alerts, and prevent malicious activity.

Question 24

Examine the exhibit above.

​“Device A” is an 8-port layer 2 managed switch and “Device C” is a 4-port hub.

Which of the following describes “Device B,” assuming all workstations can communicate with each under normal circumstances?

Answer 24

Router

The workstations connected to “Device A” are on a different network than the workstations connected to “Device C.” In order for these two subnets (network IDs) to be able to communicate with each other, “Device B” would need to be a router or layer 3 switch.

Question 25

You are tasked with securing a small network for a client in which the following requirements must be met:
• If a user on the private network attempts to send confidential company information to an unauthorized entity, an alert should be triggered.

• The private trusted network should not be accessible from the public untrusted network.
• If attacks are coming from the external network, the system should detect and prevent malicious activity.
• All incoming and outgoing email should be scanned for malware.

Which of the following would best meet the requirements of the client?

Answer 25

Implement a UTM appliance.

A UTM (unified threat management) appliance can perform the services required by the client in a single network-attached device. The client’s requirements can be met by purchasing a UTM appliance with identity-based access control lists (to mitigate data leaks), a firewall (to protect access to the internal network from the Internet), an IPS (to detect and prevent malicious activity from entering the network), and antivirus and anti-malware protection (to scan all email).