N10-007 Domain 5: Network Troubleshooting and Tools

Consider the network shown in the exhibit. When you run the show interfaces command on switch1, you observe a significant number of runts on the Gi0/1 interface. What does this statistic indicate? The cable connected to this interface is a cross-over cable, but it should be a straight-through cable. The cable connected to this interface is a straight-through cable, but it should be a cross-over cable. There is EMI or cross-talk on the cable connected to this interface that is corrupting frames. Collisions are occurring.

Collisions are occurring. EXPLANATION Runts are frames that are too small. (The minimum frame size required is 64 bytes.) This is commonly caused by collisions. In this scenario, the collisions are probably caused by a duplex mismatch error. EMI or cross-talk on UTP cabling usually causes CRC errors. Using the wrong type of cabling would cause the connection to go down.

You have heard about a Trojan horse program where the compromised system sends personal information to a remote attacker on a specific TCP port. You want to be able to easily tell whether any of your systems are sending data to the attacker. Which log should you monitor? Security Firewall System Application

Firewall EXPLANATION A firewall log identifies traffic that has been allowed or denied through a firewall. You can identify traffic types used by computers on your network by looking at the outgoing ports. For example, you can identify servers that are running a specific service, or you can see computers that are communicating using ports that might indicate malicious software. A system log records operating system, system, and hardware events. A security log records information related to logons, such as incorrect passwords being used, and the use of user rights. An application log records actions performed by an application. For each of these logs, the Trojan horse program will likely be written in a way that little or no logging will be recorded by the program, so examining these logs will not give you much information about the program on a system.

Consider the network shown in the exhibit. You have been experiencing intermittent connectivity issues with switch2. To check the status of the interfaces, you run the following commands: switch2# show interfaces fa0/1 status Port Name Status Vlan Duplex Speed Type Fa0/1 connected 3 a-half a-100 10/100BaseTX switch2# show interfaces Gi0/1 status Port Name Status Vlan Duplex Speed Type Gi0/1 connected trunk a-full a-1000 1000BaseTX switch2# show interfaces Gi0/2 status Port Name Status Vlan Duplex Speed Type Gi0/2 connected trunk a-full a-1000 1000BaseTX What is the issue with this network? There is a duplex mismatch on the Gi0/2 interface. The device connected to the Fa0/1 interface has auto-negotiation disabled. The device connected to the Gi0/1 interface has auto-negotiation disabled. There is a link speed mismatch on the Gi0/1 interface. There is a link speed mismatch on the Gi0/2 interface.

The device connected to the Fa0/1 interface has auto-negotiation disabled. EXPLANATION A duplex mismatch probably exists on the Fa0/1 interface. Note that duplexing has been automatically set to half, which is the default behavior for Cisco devices when auto-negotiation fails. To fix the issue, check the Gi0/1 interface on router1 to see if auto-negotiation has been disabled. You could manually configure the Fa0/1 interface on switch2 to use the same duplexing and link speed settings as the interface on the router, or you could re-enable auto-negotiation on the router interface. The Gi0/1 and Gi0/2 interfaces on switch2 appear to be functioning correctly with full duplexing and full link speed automatically configured.

Which TCP/IP utility gives you the following output? Interface: 192.168.4.101 on Interface 0x3 Internet Address Physical Address Type 192.168.1.23 00-d1-b6-b7-c2-af dynamic tracert ipconfig nslookup arp

arp EXPLANATION This output is displayed when you use the arp -a command to look at the ARP cache.

Which of the following tools would you use to view the MAC addresses associated with IP addresses that the local workstation has contacted recently? arping nbtstat netstat arp

arp EXPLANATION Use the arp command to view the MAC addresses associated with IP addresses that the local workstation has contacted recently. When a workstation uses ARP to find the MAC address of an IP address, it places that information in its ARP table. Use the arping command to send an ARP request to a specified IP address. arping works much like ping in that the host with the specified IP address will respond. netstat shows IP-related statistics including incoming and outgoing connections and active sessions, ports, and sockets. nbtstat displays the NetBIOS name tables for both the local computer and remote computers and the NetBIOS name cache.

You work in an office that uses Linux servers and Windows servers. The network uses both the TCP/IP protocol. The Linux server is used as an FTP server. Today you have received several calls from people who are unable to contact the Linux server at its known IP address. You are sitting at the Linux server and want to check its IP address. Which command should you use? ipconfig ifconfig winipcfg route

ifconfig EXPLANATION Use the ifconfig command to show the TCP/IP configuration for a Linux computer.

Which TCP/IP utility gives you the following output? Active Connections netstat -r nbtstat -c netstat -a arp -a

netstat -a EXPLANATION netstat -a shows you the status of all connections and listening ports.

Mary calls to tell you that she can't connect to an intranet server called WebSrv1. From her computer, you ping the server's IP address. The ping test is successful. Which tool would you use on her workstation next to troubleshoot the problem? nslookup tracert netstat arp nbtstat

nslookup EXPLANATION Use nslookup to troubleshoot name resolution problems. Because the ping test was successful, you know that both the client and the server can communicate using TCP/IP with IP addresses. This tells you that the problem is related to name resolution.

Consider the following output from a dig command run on a Linux system. ; <<>> DiG 8.2 <<>> westsim111.com ;;res options:init recurs defnam dnsrch ;;got answer: ;;->>HEADER<<-opcode:QUERY, status: NOERROR, id:4 ;;flags: qr rd ra; QUERY:1, ANSWER:1, AUTHORITY:2, ADDITIONAL:0 ;;QUERY SECTION: ;; westsim111.com, type = A, class = IN ;;ANSWER SECTION: westsim111.com. 7h33m IN A 76.141.43.129 ;;AUTHORITY SECTION: westsim111.com. 7h33m IN NS dns1.deriatct111.com. westsim111.com. 7h33m IN NS dns2.deriatct222.com. ;;Total query time: 78 msec ;;FROM: localhost.localdomain to SERVER:default -- 202.64.49.150 ;;WHEN: Tue Feb 16 23:21:24 2005 ;;MSG SIZE sent: 30 rcvd:103 What is the IP address of the DNS server that performed this name resolution? 76.141.43.129 202.64.49.150 192.168.1.100 16.23.21.24

202.64.49.150 EXPLANATION When the dig command is used to perform a manual DNS lookup, a range of information is provided. The IP address of the DNS server that performed the name resolution is shown in the bottom area of the output, on the end of the ;;FROM line. The IP address shown in the answer section denotes the resolved IP address for the domain or host for which the resolution was requested. In this case, that address is 76.141.43.129. The other two answers are invalid.

You are troubleshooting a wireless connectivity issue in a small office. You determine that the 2.4GHz cordless phones used in the office are interfering with the wireless network transmissions. If the cordless phones are causing the interference, which of the following wireless standards could the network be using? (Select two.) 802.11b 802.11a Bluetooth Infrared 802.3a

802.11b Bluetooth EXPLANATION Both the 802.11b and Bluetooth wireless standards use the 2.4 GHz RF range to transmit data. Cordless phones that operate at the same frequency can cause interference on the wireless network. Other devices, such as microwaves and electrical devices, may also cause interference. 802.11a uses the 5 GHz radio frequency, so they would not be affected by the 2.4 GHz phones used in the office. Infrared uses a light beam to connect computer and peripheral devices to create a personal area network (PAN).

After installing a new 2.4Ghz cordless phone system in your office, you notice that wireless network performance is adversely affected. Which of the following wireless networking standards are you most likely using? (Select two.) Bluetooth 802.11g 802.11b 802.11a

802.11g 802.11b EXPLANATION Both the 802.11b and 802.11g wireless networking standards use the 2.4Ghz frequency range. A cordless phone system on the same frequency range may affect the performance of the wireless network. 802.11a uses the 5Ghz frequency range, so it would not be affected by a cordless phone system that uses the 2.4Ghz frequency range. Bluetooth does use the 2.4Ghz frequency range, but is used more widely as a mechanism to connect consumer electronic devices like personal digital assistants (PDAs), cameras, and phones, rather than as a wireless local area networking (LAN) method.

Review the output from the show interfaces fa0/1 command on the switch2 switch in the exhibit. What is wrong with the fa0/1 interface in this example? The line status is administratively down. A duplex mismatch exists with the device on the other end of the connection. The cable connecting the fa0/1 interface with the device on the other end is a straight-through cable, but needs to be crossed-over. The protocol status is down.

A duplex mismatch exists with the device on the other end of the connection. EXPLANATION In this example, the following statistics indicate that a duplex mismatch error has occurred: Duplexing is set to half. There are a significant number of runts. There are a significant number of collisions. There are a significant number of late collisions.

You have decided to conduct a business meeting at a local coffee shop. The coffee shop you chose has a wireless hotspot for customers who want internet access. You decide to check your email before the meeting begins. When you open the browser, you cannot gain internet access. Other customers are using the internet without problems. You are sure your laptops wireless adapter works because you use a wireless connection at work. What is the likely cause of the problem? Antenna strength on the WAP is too low. PPP is not configured correctly. A mismatched SSID. WAP is out of range. Different LAN protocols are being used.

A mismatched SSID. EXPLANATION A wireless client and the access point must be configured to use the same SSID. In this case, the client system was used on a different wireless network and may still be using the SSID from that network. To log onto this network, the system will need to be configured to use the same SSID as other customers in the coffee shop. Sometimes the SSID will automatically be detected by a wireless monitoring program. As a new SSID is detected, it will attempt to connect and use the new SSID and new access point. When this does not happen, you need to change the the SSID manually. The problem is not with LAN protocols, as TCP/IP is the protocol used on the internet, so there are no other choices. The WAP is not out of range, as other clients are accessing it. PPP is not required to make the internet connection.

You administer a network with Windows Server 2016 and UNIX servers and Windows 10 Professional, Windows 7, and Macintosh clients. A Windows 7 computer user calls you one day and says he is unable to access resources on the network. You type ipconfig on the user's computer and receive the following output: 0 Ethernet adapter: IP address. . . . . . . . . : 169.254.1.17 Subnet Mask . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . : You also check your NIC and see the link light on. What might the problem be? The user changed the configuration of the computer. A misconfigured DNS server. An unavailable DHCP server. A bad NIC. A missing default gateway.

An unavailable DHCP server. EXPLANATION If a Windows 7 client computer is configured to use DHCP and cannot locate one to receive IP addressing information, it assigns itself an IP address from the APIPA (Automatic Private IP Addressing) range of IP addresses. APIPA addresses include IP addresses from 169.254.0.0 to 169.254.255.254 and are reserved for this purpose. A lit link light on your NIC indicates a connection to the network.

You are creating an Ethernet network for your company. The shipping department is located in a different building that is located 150 meters from the main wiring closet. You use a single Cat6e cable to connect the wiring closet to the shipping building. Which of the following conditions are you most likely to experience? Crosstalk Open circuit Attenuation Impedance mismatch

Attenuation EXPLANATION Attenuation is the loss of signal strength from one end of a cable to the other. The longer the cable, the more attenuation. For this reason, it is important to not exceed the maximum cable length defined by the networking architecture. In this example, the distance from the wiring closet to the other building exceeds the 100 meter maximum for Ethernet. Impedance is the measure of resistance within the transmission medium. An impedance mismatch occurs when you use cables and devices with different impedance values. When signals move from one cable to another with a different impedance rating, some of the signal is reflected back to the transmitter, distorting the signal. Crosstalk is interference that is caused by signals within the twisted pairs of wires. An open circuit is a cut in the wire that prevents the original signal from reaching the end of the wire. If you have a short, the signal travels a different path. But if you have an open circuit, the signal does not travel anywhere because electricity cannot flow when the path is disconnected.

You manage a network that uses 1000BaseT Ethernet. You find that one device communicates on the network at only 100 Mbps. Which tool should you use to test the drop cable and the connection to the network? TDR Cable tester Certifier Multimeter Toner probe

Certifier EXPLANATION A cable certifier is a multi-function tool that verifies or validates that a cable or an installation meets the requirements for a specific architecture implementation. For example, you would use a certifier to verify that a specific drop cable meets the specifications for 1000BaseT networking. A cable tester verifies that the cable can carry a signal from one end to the other and that all wires are in their correct positions. A toner probe is two devices used to trace the end of a wire from a known endpoint into the termination point in the wiring closet. A time domain reflector (TDR) measures the length of a cable or to identify the location of a fault in the cable. A multimeter measures the electrical properties of a device, including voltage, amps, and resistance.

A user reports that she can't connect to the Internet. After some investigation, you find that the wireless router has been misconfigured. You are responsible for managing and maintaining the wireless access point. What should you do next? Fix the problem. Determine if escalation is needed. Create an action plan. Document the problem.

Create an action plan. EXPLANATION At this point, you should create an action plan and account for side effects of the proposed plan. Identifying the affects ahead of time helps you put measures into place to eliminate or reduce any potential negative consequences. Escalation is not necessary because you are already in charge of managing the wireless access point, and the problem is isolated to that device. Fix the problem only after creating the action plan and identifying possible effects. Document the problem and the solution after the problem has been fixed and the solution has been verified.

You have decided to implement Gigabit Ethernet on your network. Each switch port is connected to a single device. Following the installation, you find one device connected to a switch that is only running at 100 Mbps. Which of the following are likely causes? Short Incorrect VLAN Collisions Switching loop Crosstalk

Crosstalk EXPLANATION Crosstalk is interference caused by signals within the twisted pairs of wires. For example, current flow on one wire causes a current flow on a different wire. Crosstalk and other miswiring problems typically mean that a cable does not operate at the desired standard. Use a cable certifier to verify that that cable is properly configured to support the rated speed. A short is where the signal is received on an incorrect wire. A short will typically mean the cable does not work at all or communications are very limited and extremely slow. Collisions are eliminated when you connect a single device to each switch port. A switching loop occurs when there are multiple active paths between two switches. Switching loops lead to incorrect entries in a MAC address table, making it appear that a device is connected to the wrong port and causing unicast traffic to circulate in a loop between switches. VLANs create logical groupings of computers based on switch port. Because devices on one VLAN cannot communicate with devices in different VLANs, incorrectly assigning a port to a VLAN might prevent a device from communicating through the switch.

Users report that the network is down. As a help desk technician, you investigate and determine that a specific router is configured so that a routing loop exists. What should you do next? Determine if escalation is needed. Document the problem. Create an action plan. Fix the problem.

Determine if escalation is needed. EXPLANATION After identifying the most probable cause, escalate the problem if it is beyond your ability to fix or if it is out of your scope of management. For example, the problem might be in a router configuration that you are not authorized to correct. When forwarding the problem on to someone else, be sure to describe the nature of the problem, the actions you have already taken, and the symptoms that lead you to believe the problem is outside of your area of responsibility. If you decide that escalation is not necessary, you can then create an action plan that includes the fix and identifying possible effects of implementing the fix. After the solution has been implemented, verify that it works and that there were no unforeseen consequences. Finally, document the problem and the solution.

A user reports that she can't connect to a server on your network. You check the problem and find out that all users are having the same problem. What should you do next? Determine what has changed. Identify the affected areas of the network. Create an action plan. Establish the most probable cause.

Determine what has changed. EXPLANATION At this point, you have identified the symptoms and the scope of the problem. In this scenario, you have determined that the problem affects all users. The next step is to determine what might have changed that could have caused the problem. You have already identified the affected area because you know that the problem affects all users. Before you can choose a probable cause, do additional work to see what might have changed. After selecting a probable cause, determine if escalation is required. Then create an action plan and fix the problem.

Which of the following enterprise wireless deployment models uses access points with enough intelligence to allow the creation of guest WLANs for keeping public wireless traffic separate from private traffic? Independent access points Distributed wireless mesh infrastructure Lightweight access point (LWAP) with wireless controller infrastructure Hub-and-spoke infrastructure

Distributed wireless mesh infrastructure EXPLANATION A distributed wireless mesh architecture moves some of the network intelligence from the controller out to the individual access points. In this configuration, the controller is no longer a bottleneck. The APs are smart enough to communicate directly with each other to create more efficient data paths for network traffic. With the hub-and-spoke infrastructure, the individual access points contain very little embedded intelligence and are sometimes referred to as lightweight access points (LWAPs). Independent access points offer limited mobility and require the individual configuration of each AP.

A user reports that network access from her workstation is very slow. The problem does not seem to be affecting any other users. Which of the following conditions is the most likely cause? Duplex mismatch Switching loop Broadcast storm Incorrect VLAN

Duplex mismatch EXPLANATION A duplex mismatch occurs when two devices are using different duplex settings. In this case, one device will try to transmit using full-duplex, while the other will expect half-duplex communications. Symptoms of a duplex mismatch include very slow network communications. Ping tests might appear to complete correctly, but normal communications work well below the expected speeds, even for half-duplex communications. A switching loop occurs when there are multiple active paths between two switches. Switching loops lead to incorrect entries in a MAC address table, making a device appear to be connected to the wrong port, and causing unicast traffic to be circulated in a loop between switches. A broadcast storm is excessive broadcast traffic that renders normal network communications impossible. Broadcast storms can be caused by switching loops that cause broadcast traffic to be circulated endlessly between switches or Denial of Service (DoS) attacks. For both switching loops and broadcast storms, the problem would not be isolated to a single device, but the problem would exist for most devices. VLANs create logical groupings of computers based on switch port. Devices can only communicate with other devices that are members of the same VLAN. In this scenario, the problem is that network access is slow, not that devices cannot be accessed.

You are reviewing the output of the show interfaces command for the Gi0/1 interface on a switch. You notice a significant number of CRC errors displayed. What are the most likely causes? (Select two. Each response is a complete solution.) EMI or cross-talk on the cable connected to the interface. Collisions. The device on the other end of the cable is powered off or the other interface is administratively shutdown. The cable connected to this interface is a cross-over cable, but should be a straight-through cable. The cable connected to this interface is a straight-through cable, but should be a cross-over cable.

EMI or cross-talk on the cable connected to the interface. Collisions. EXPLANATION CRC errors are received frames that did not pass the FCS check. These are usually caused by collisions, but they can also be caused by EMI or cross-talk on UTP cabling. All of these conditions can damage frames on the wire, causing a CRC error. Using the wrong type of cabling would cause the link to go down. A disabled interface on the other end of the cable would also cause the link to go down.

You have a cable internet connection at home. The installer had connected the router near the outside wall of your house with RG6 cable. You move the cable router a distance of 50 meters using RG8 cables and special connector adapters. Which condition are you most likely to experience? FEXT EMI Echo Attenuation NEXT

Echo EXPLANATION An impedance mismatch (manifested by echo) occurs when you connect cables and devices that have a different impedance (resistance) rating. Impedance is mostly a factor in coaxial cables used for networking. Be sure to choose cable with the correct rating (50 or 75 ohm) based on the network type, and do not mix cables with different ratings. RG6 cables have a rating of 75 ohms, while RG-8 cables have a rating of 50 ohms. Attenuation is the loss of signal strength from one end of a cable to the other. Electromagnetic interference (EMI) is interference that comes from an external source. Common sources of EMI include nearby generators, motors (such as elevator motors), radio transmitters, welders, transformers, and fluorescent lighting. Near-end crosstalk (NEXT) is crosstalk measured on the same end as the transmitter. For example, when a signal is sent on one wire, near-end crosstalk measures the interference on another wire at the same connector near the source of the original signal. Far-end crosstalk (FEXT) is crosstalk measured on the opposite end from the transmitter. For example, when a signal is sent on one wire, far-end crosstalk measures the interference on another wire at the opposite end from the source signal.

You are a network administrator for your company. A frantic user calls you one morning exclaiming that nothing is working. What should you do next in your troubleshooting strategy? Recognize the potential effects of the problem. Establish the symptoms. Identify the affected area. Establish what has changed.

Establish the symptoms. EXPLANATION Currently, you have no idea what problem the user is having. For all you know, the user's electric pencil sharpener could be malfunctioning. You need to establish the symptoms first.

Upon conducting a visual inspection of the server room, you see that a switch displays LED collision lights that are continually lit. You check the LED on the corresponding workstation and see that it is flashing rapidly even though it is not sending or receiving network traffic at that time. What is the cause of the network collisions? Incorrect duplex settings PCI slot failure Adapter controller card failure Faulty switch Faulty network card

Faulty network card EXPLANATION Sometimes when a NIC fails, it doesn't just stop working, but begins to flood the network with transmissions. This is called jabbering. A single network card can slow down and entire network by continually transmitting onto the network. A jabbering network card can be identified by a slower than normal network, by high occurrences of collisions displayed on the hub or switch, and by LEDs on a network card indicating a high level of transmissions even though a user is not using the network.

A router periodically goes offline. Once it goes offline, you find that a simple reboot puts the router back online. After doing some research, you find that the most likely cause of the problem is a bug in the router software. A new patch is available from the manufacturer that is supposed to eliminate the problem. What should you do next? Document the problem and the solution. Identify the affected areas. Identify possible effects of the solution. Apply the patch to the router.

Identify possible effects of the solution. EXPLANATION Based on the troubleshooting process, you should create an action plan and identify possible effects of implementing the solution. For example, you might consider how long the router will be offline to apply the patch, how long it will take to implement the solution, and what problems that might occur during the process. Take the action to fix the problem only after you have created the plan, identified the effects, and determined the best time to implement the fix. Document the solution after the problem is fixed and verified. Identifying the affected areas is part of the process you take before arriving at a probable solution.

A user reports that he can't connect to a specific website. You go to the user's computer and reproduce the problem. What should you do next? Determine if escalation is necessary. Establish the most probable cause. Determine if anything has changed. Identify the affected areas of the network.

Identify the affected areas of the network. EXPLANATION After identifying the problem, identify the affected area and determine how large the problem is. For example, is the problem limited to this one user, or does it affect all users or a group of users? After identifying the affected area, find out if anything has changed that might cause the problem. At this point, you should have enough information that you can select a probable cause and determine if escalation is necessary.

Which of the following tests can be performed by a TDR? (Select two.) Measure near end and far end crosstalk. Verify that the cable meets Cat5e, Cat6, or Cat7 standards. Identify split pairs and miswires. Identify the location of a fault on a cable. Measure the length of a cable.

Identify the location of a fault on a cable. Measure the length of a cable. EXPLANATION A TDR is a special device that sends electrical pulses on a wire in order to discover information about the cable. The TDR measures impedance discontinuities, the echo received on the same wire in response to a signal on the wire. The results of this test can be used to: Estimate the length of a wire. Measure the cable impedance. Identify the locations of splices and connectors on the wire. Identify shorts and open circuits and the location of the fault. Use a cable certifier to verify that a cable meets Cat5e, Cat6, or Cat6e standards, especially to make sure that crosstalk is within acceptable levels. Use a cable tester to check for miswires and split pairs. Many cable certifiers and some cable testers also include a TDR.

A user is unable to connect to the network. You investigate the problem and determine that the network adapter is defective. You replace the network adapter and verify that it works. What should you do next? Create an action plan. Document the problem and solution. Identify the results and effects of the solution. Determine if escalation is necessary.

Identify the results and effects of the solution. EXPLANATION After implementing and testing the solution, identify the results and effects of the solution. Make sure that the solution has fully fixed the problem and has not caused any other problems. Document the problem and solution after it has been fixed and verified. Determine if escalation is needed and create an action plan before implementing the solution.

Which of the following are reasons to use a protocol analyzer? (Select two.) Identify when a network is slow. Identify users that are connecting to unauthorized websites. Measure the amount of data that can be transferred through a network. Simulate a large number of client connections to a website. Find devices that might be using legacy protocols, such as IPX/SPX or NetBIOS.

Identify users that are connecting to unauthorized websites. Find devices that might be using legacy protocols, such as IPX/SPX or NetBIOS. EXPLANATION A protocol analyzer is a device that copies frames and allows you to view frame contents. Use a protocol analyzer to: Find devices that might be using restricted protocols (such as ICMP) or legacy protocols (such as IPX/SPX or NetBIOS). Identify frames that might cause errors. Examine the data contained within a packet (for example, to identify users that are connecting to unauthorized websites). Troubleshoot communication problems or investigate the source of heavy network traffic. Use a throughput tester to measure the amount of data that can be transmitted on a network, which can help you identify when a network is slow. A load tester can be used to simulate a large number of client connections to a website.

A workstation is connected to a switch on the Gi 0/2 interface using a straight-through cable. The Ethernet interface in the workstation has been manually configured to use a 100 Mbps link speed in full-duplex mode. Which of the following are true in this scenario? (Select three.) If the link speed is 10 Mbps or 100 Mbps, half-duplex is used. The switch interface will display as administratively down. If the link speed is 10 Mbps or 100 Mbps, full-duplex is used. If the link speed is 1000 Mbps or faster, half-duplex is used. If the link speed is 1000 Mbps or faster, full-duplex is used. The switch attempts to sense the link speed. If it can't, the slowest link speed supported on the interface is selected.

If the link speed is 10 Mbps or 100 Mbps, half-duplex is used. If the link speed is 1000 Mbps or faster, full-duplex is used. The switch attempts to sense the link speed. If it can't, the slowest link speed supported on the interface is selected. EXPLANATION By default, the link speed and duplex configuration for Ethernet interfaces in Cisco devices are set using IEEE 802.3u auto-negotiation. The interface negotiates with remote devices to determine the correct settings. However, auto-negotiation can be disabled on the Cisco device and/or other Ethernet network hosts. When this happens, devices with auto-negotiation enabled try to negotiate link speed and duplexing, but get no response. When auto-negotiation fails, Cisco devices that have auto-negotiation enabled default to the following: If possible, the interface attempts to sense the link speed. If this is not possible, the slowest link speed supported on the interface is used, which is usually 10 Mbps. If the selected link speed is 10 Mbps or 100 Mbps, then half-duplex is used. If it is 1000 Mbps or faster, then full-duplex is used. In this situation, link speed and duplex mismatches are likely to occur between network devices on the same link. When this happens, the link will probably be established and the interface will be in an up/up state, but it will perform very poorly.

Your wireless network consists of multiple 802.11n access points that are configured as follows: SSID (hidden): CorpNet Security: WPA2-PSK using AES Frequency: 5.75 GHz Bandwidth per channel: 40 MHz Because of the unique construction of your organization's facility, there are many locations that do not have a clear line of sight between network clients and access points. As a result, radio signals are reflected along multiple paths before finally being received. The result is distorted signals that interfere with each other. What should you do? Switch to RADIUS authentication for wireless clients. Reduce the power of the access point radio signals. Implement antenna diversity. Install directional access points.

Implement antenna diversity. EXPLANATION Antenna diversity implements two or more radio antennae to improve the quality and reliability of a wireless link. In environments where there is no clear line of sight between transmitter and receiver, the radio signal is reflected along multiple paths before finally being received. This can introduce phase shifts, time delays, attenuation, and distortion that interfere with each another on the receiving antenna. You can rectify the situation by implementing antenna diversity two ways: Spatial diversity uses multiple antennas that are physically separated from one another. Pattern diversity uses two or more co-located antennas with different radiation patterns. Using a RADIUS authentication solution increases wireless network security, but it doesn't address the issue of multipath interference. Reducing radio power could help solve multipath interference issues in some situations, but it may make it worse in others. This is also true of directional access points.

A user reports that he can't browse to a specific website on the internet. From his computer, you find that a ping test to the web server succeeds. A traceroute test shows 17 hops to the destination web server. What is the most likely cause of the problem? Incorrect default gateway address Incorrect DNS server address Duplicate IP addresses Incorrect subnet mask value

Incorrect DNS server address EXPLANATION In this scenario, a ping test to the website succeeds, while accessing the website through the browser does not work. Users type host names in the browser to go to websites, but host names must be translated to IP addresses by a DNS server. Either the workstation is using the wrong address for the DNS server, the DNS server is not available, or the DNS server does not have an entry for the website. Because the ping and traceroute tests work, you know that the IP address, subnet mask, and default gateway values are correct.

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation cannot communicate with any other host on the network. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix. : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled. . . . . . . : No Autoconfiguration Enabled . . : Yes IPv4 Address. . . . . . . : 192.168.2.102(Preferred) Subnet Mask . . . . . . . : 255.255.255.0 Default Gateway. . . . . . : 192.168.1.1 DNS Servers . . . . . . . : 192.168.2.20 What is the most likely cause of the problem? Incorrect IP address Incorrect subnet mask Incorrect DNS server address Incorrect default gateway

Incorrect IP address EXPLANATION In this example, the IP address assigned to the host is on the wrong subnet. The host address is on the 192.168.2.0/24 subnet, but the other devices are using addresses on the 192.168.1.0 subnet (the scenario states that you are connecting the workstation to this subnet).

You manage a local area network with several switches. A new employee has started today, so you connect her workstation to a switch port. After connecting the workstation, you find that the workstation cannot get an IP address from the DHCP server. You check the link and status lights and see that the connection is working properly. A ping to the loopback address on the workstation succeeds. No other computers seem to have the problem. Which of the following is the most likely cause of the problem? Half-duplex setting on the switch and workstation Incorrect VLAN assignment Incorrect default gateway setting Switching loop

Incorrect VLAN assignment EXPLANATION The most likely cause is that the switch port is a member of a VLAN that is different from the VLAN for the DHCP server and other devices. It is possible that unused ports on the switch were assigned to a VLAN that is different from the VLAN used by other devices. The duplex setting would probably not prevent traffic between the workstation and the switch; it would simply mean that both devices would perform collision detection. A problem might occur if one device were manually configured for full-duplex, and the other were configured for half-duplex. A switching loop occurs when there are multiple active paths between two switches. Switching loops lead to incorrect entries in a MAC address table, making a device appear to be connected to the wrong port and causing unicast traffic being circulated in a loop between switches. Switching loops would typically affect multiple devices, not just one. The default gateway setting affects whether the device can communicate with hosts on different subnets, but this value is typically received from the DHCP server.

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation can communicate with some hosts on the private network, but not with other hosts. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address. . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled . . . . . . . : No Autoconfiguration Enabled. . . : Yes IPv4 Address . . . . . . . : 192.168.1.102(Preferred) Subnet Mask . . . . . . . : 255.255.255.0 Default Gateway. . . . . . . . . : 192.168.2.1 DNS Servers. . . . . . . . . . . : 192.168.2.20 What is the most likely cause of the problem? Incorrect IP address Incorrect subnet mask Incorrect DNS server address Incorrect default gateway

Incorrect default gateway EXPLANATION In this example, the default gateway address is incorrect. The default gateway address must be on the same subnet as the IP address for the host. The host address is on the 192.168.1.0/24 subnet, but the default gateway address is on the 192.168.2.0 subnet.

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation can communicate with some hosts on the private network, but not with other hosts. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address. . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled . . . . . . . : No Autoconfiguration Enabled. . . : Yes IPv4 Address . . . . . . . : 192.168.1.102(Preferred) Subnet Mask. . . . . . . . : 255.255.0.0Default Gateway . . . . . . : 192.168.1.1 DNS Servers . . . . . . . : 192.168.1.20 192.168.1.27 What is the most likely cause of the problem? Incorrect subnet mask Incorrect DNS server address Incorrect default gateway Incorrect IP address

Incorrect subnet mask EXPLANATION In this example, the network is using a mask of 255.255.255.0 (24-bits), but the workstation is configured to use a mask of 255.255.0.0.

Match each type of access point on the left with the wireless network architecture where it is commonly used on the right. Each type of access point may be used once, more than once, or not at all. Drag: Intelligent AP Lightweight AP Drop: Independent access point infrastructure Hub-and-spoke infrastructure Distributed wireless mesh infrastructure

Independent access point infrastructure - Intelligent AP Hub-and-spoke infrastructure - Lightweight AP Distributed wireless mesh infrastructure - Intelligent AP EXPLANATION Different types of access points are used in different wireless network architectures, as described in the following table: Independent Access Points - In the early days of wireless networking, large organizations implemented independent access points throughout their facilities. Each AP stood alone, providing separate wireless networks using its own independent configuration. Hub-and-Spoke Infrastructure - In a hub-and-spoke configuration, a wireless controller is connected to all access points using wired links. The individual access points contain very little embedded intelligence and are sometimes referred to as lightweight access points (LWAPs). Distributed Wireless Mesh Infrastructure - Newer wireless networks can be deployed using a distributed wireless mesh architecture. These networks still use a controller, but they move some of the network intelligence from the controller out to the individual access points. In this configuration, the controller is no longer a bottleneck. The APs are smart enough to communicate directly with each other to create more efficient data paths for network traffic.

Users are complaining that sometimes network communications are slow. You use a protocol analyzer and find that packets are being corrupted as they pass through a switch. You also notice that this only seems to happen when the elevator is running. What should you do? Install shielded cables near the elevator. Add a UPS system to the switch. Add a dedicated A/C unit to the switch closet. Install a dedicated power circuit for the switch.

Install shielded cables near the elevator EXPLANATION Interference is a signal that corrupts or destroys regular networking signals. Interference affects the availability of a network because normal communications are not possible. Sources of interference include elevators, generators, motors, and fluorescent lights. Use a UPS or a dedicated power circuit to ensure that devices have constant power. Use a dedicated A/C unit to keep a server room or closet cool.

You are troubleshooting an IP addressing issue and issue a command to view the TCP/IP configuration of the system. The command you use produces the following output: fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 inet6 fe80::2a0:83ff:fe30:57a%fxp0 prefixlen 64 scopeid 0x1 inet 192.168.1.235 netmask 0xfffffc00 broadcast 255.255.255.255 ether 00:a0:83:30:05:7a media: Ethernet autoselect (100baseTX <full-duplex>) status: active lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 inet6 ::1 prefixlen 128 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x7 inet 127.0.0.1 netmask 0xff000000 Which of the following operating systems are you working on? Linux Windows Server 2012 Windows 10 Windows Server 2016

Linux EXPLANATION The output shown is from the ifconfig command run on a Linux system. The equivalent command on Windows 10, Windows 2012, and Windows Server 2016 is ipconfig.

You have a website that customers use to view product information and place orders. You would like to identify the maximum number of simultaneous sessions that this server can maintain before performance is negatively impacted. Which tool should you use? System log Packet sniffer Baseline Throughput tester Load tester

Load tester EXPLANATION A load tester simulates a load on a server or service. For example, the load tester might simulate a large number of client connections to a website, test file downloads for an FTP site, or simulate large volumes of email. Use a load tester to make sure that a system has sufficient capacity for expected loads, and even to estimate a failure point where the load is more than the system can handle. A throughput tester measures the amount of data that can be transferred through a network or processed by a device (such as the amount of data that can be retrieved from disk in a specific period of time). A packet sniffer is special software that captures (records) frames that are transmitted on the network. A baseline is a snapshot of past performance statistics of the network or devices. A system log identifies events or actions performed on a device.

Match each wireless device on the left with its corresponding characteristics on the right. Each device may be used once, more than once, or not at all. Drag: Consumer-grade (SOHO) wireless router Wireless controller Drop: Manages all of the APs that are connected to it. Supports 30 to 50 wireless clients per access point. Provides NAT routing and an Ethernet switch in one device. Supports a maxiumum of 5-10 wireless clients. Pushes wireless configuration settings to connected access points.

Manages all of the APs that are connected to it. - Wireless controller Supports 30 to 50 wireless clients per access point. - Wireless controller Provides NAT routing and an Ethernet switch in one device. - Consumer-grade (SOHO) wireless router Supports a maxiumum of 5-10 wireless clients. - Consumer-grade (SOHO) wireless router Pushes wireless configuration settings to connected access points. - Wireless controller EXPLANATION When you implement a wireless network, you should use the appropriate equipment for the type of deployment. The equipment used in an enterprise wireless network is very different from the wireless equipment used in homes or small businesses. For home or small business wireless networks, you typically use a consumer-grade SOHO wireless router that combines many functions into a single device, including a: Wireless access point Ethernet switch NAT router These devices work reasonably well in small environments. However, they have very limited capacity, typically supporting a maximum of 5-10 wireless clients at a time. If you connect more clients than this, the bandwidth of the entire wireless network is severely impacted. In a larger deployment, you must use high-end equipment designed to support a larger number of users. For example, a wireless controller is typically deployed that manages a large number of individual access points. A wireless controller: Manages all of the APs that are connected to it. Supports 30 to 50 wireless clients per access point. Some manufacturers' equipment can support up to 80 clients per access point. Pushes wireless configuration settings to connected access points.

You decide to use a packet sniffer to identify the type of traffic sent to a router. You run the packet sniffing software on a device that is connected to a hub with three other computers. The hub is connected to the same switch that is connected to the router. When you run the software, you see frames addressed to the four workstations, but not to the router. Which feature should you configure? Mirroring Spanning tree Promiscuous mode Bonding

Mirroring EXPLANATION A switch will only forward packets to the switch port that holds a destination device. This means that when your packet sniffer is connected to a switch port, it will not see traffic sent to other switch ports. To configure the switch to send all frames to the packet sniffing device, configure port mirroring on the switch. Port mirroring makes it so all frames sent to all other switch ports will be forwarded on the mirrored port. Promiscuous mode configures a network adapter to process every frame it sees, not just the frames addressed to that network adapter. In this scenario, you know that the packet sniffer is running in promiscuous mode because it can already see frames sent to other devices. Bonding logically groups two or more network adapters to be used at the same time for a single logical network connection. Spanning tree runs on a switch and ensures that there is only one active path between switches, allowing redundant paths

Match the wireless networking term or concept on the left with its appropriate description on the right. Each term may be used once, more than once, or not at all. Drag: Device density Roaming LWAPP VLAN pooling Wireless bridge Heat map Goodput Drop: Moving an wireless device between access points within the same wireless network. Used by Cisco wireless equipment to route frames back and forth between the wireless network and the wired LAN. Specifies the number of clients that utilize the wireless network. Automatically partitions a single broadcast domain into multiple VLANs. Graphically displays wireless signal strength within an area. Connects two wired networks over a Wi-Fi network. Identifies relative strength of a radio signal at the receiver. The number of useful bits delivered from sender to receiver within a specified amount of time.

Moving an wireless device between access points within the same wireless network. - Roaming Used by Cisco wireless equipment to route frames back and forth between the wireless network and the wired LAN. - LWAPP Specifies the number of clients that utilize the wireless network. - Device density Automatically partitions a single broadcast domain into multiple VLANs. - VLAN pooling Graphically displays wireless signal strength within an area. - Heat map Connects two wired networks over a Wi-Fi network. - Wireless bridge Identifies relative strength of a radio signal at the receiver. - Heat map The number of useful bits delivered from sender to receiver within a specified amount of time. - Goodput EXPLANATION You should be familiar with the following wireless networking terms and concepts: Device density specifies the number of clients that utilize the wireless network. Roaming is moving an wireless device between access points within the same wireless network. The Lightweight Access Point Protocol (LWAPP) is used by Cisco wireless equipment to route frames back and forth between the wireless network and the wired LAN. VLAN pooling automatically partitions a single broadcast domain into multiple VLANs. A wireless bridge connects two wired networks over a Wi-Fi network. A heat map graphically displays the relative wireless signal strength within a wireless deployment. Goodput refers to the number of useful bits delivered from the sender to the receiver within a specified amount of time.

You want to measure the voltage, amps, and ohms of various devices. Which tool should you use? Certifier Butt set Voltage event recorder Toner probe Multimeter

Multimeter EXPLANATION A multimeter is a device that tests various electrical properties. For example, most multimeters can measure: AC and DC voltage Current (amps) Resistance (ohms) Capacitance Frequency A voltage event recorder tracks voltage conditions on a power line. Basic recorders keep track of the occurrence of under or over voltage conditions, while more advanced devices track conditions over time and create a graph, saving data from a program running on a computer. A butt set (also called a lineman's handset) is a device used to test analog telephone installations. The butt set includes an earpiece, mouthpiece, dialing interface, and various connectors. A toner probe is two devices used to trace the end of a wire from a known endpoint into the termination point in the wiring closet. A cable certifier is a multi-function tool that verifies or validates that a cable or an installation meets the requirements for a specific architecture implementation.

You are building a new network for a small startup financial services company. Security is paramount, so each organization within the company will have its own network segment separated by a router. However, funds are limited, and you have been asked to keep costs to a minimum. You have acquired a used fiber optic switch and want to use it to create a fiber optic backbone that interconnects all of the routers. You purchased several used single-mode GBIC modules on eBay that you will install in each router to allow them to connect to the switch. Both the switch and the GBIC modules use MTRJ connectors. You connect each module to the switch with 1-meter multimode patch cables. Will this implementation work? No. You shouldn't use multi-mode patch cables with single-mode GBIC modules. Yes,. All of the requirements for implementing a fiber optic network have been met. No. You should purchase fiber optic equipment that use FC connectors. No. You should not use standard fiber optic switches to create a backbone network for routers.

No. You shouldn't use multi-mode patch cables with single-mode GBIC modules. EXPLANATION Some GBIC/SFP modules use multi-mode fiber, while others use single-mode. You must use the correct type of fiber optic cable and connector required by the specific adapter. You cannot mix and match different types of cable. In this scenario, connecting a single-mode GBIC to multi-mode fiber will introduce a catastrophic signal loss of up to 99%.

You are setting up a wireless hotspot in a local coffee shop. For best results, you want to disperse the radio signals evenly throughout the coffee shop. Which of the following antenna types would you use on the AP to provide a 360-degree dispersed wave pattern? Multi-directional Omni-directional Uni-directional Multi-point Directional

Omni-directional EXPLANATION An omni-directional antenna provides a 360-degree dispersed wave pattern. In this configuration, signals are dispersed evenly in all directions, making this antenna well suited for environments where clients are accessing the network from various locations, such as coffee shops. A dispersed wireless signal is weaker and, therefore, is restricted to shorter signal distances. A directional wireless antenna focuses a signal in a particular direction. The focused signal allows for greater transmission distances and a stronger signal. Directional antennas are sometimes used to establish a wireless point-to-point connection where greater transmission distances are often required.

You need to place a wireless access point in your two-story building. While trying avoid interference, which of the following is the best location for the access point? Near the backup generators On the top floor In the kitchen area In the basement

On the top floor EXPLANATION In general, place access points high up to avoid interference problems caused by going through building foundations. Do not place the access point next to sources of interference such as other wireless transmitting devices (cordless phones or microwaves) or other sources of interference (motors or generators).

You have been hired to troubleshoot a wireless connectivity issue for two separate networks located within a close proximity. Both networks use a WAP from the same manufacturer, and all settings, with the exception of SSIDs, remain configured to the default. Which of the following might you suspect as the cause of the connectivity problems? Crosstalk between the RF signals. Overlapping channels. The SSIDs of the two server systems match. WEP overlap. The SSIDs of the two client systems match.

Overlapping channels. EXPLANATION Overlapping wireless networks should use different channels to ensure that they do not conflict with each other. In this case, each WAP is using the default channel which, by default, is the same for each WAP. The solution to the problem would be to configure different channels for each access point. To configure client connectivity, the wireless client and the access point must share the same SSID, channel, and WEP encryption strength. In this case, the SSIDs were changed for each station, so they are not the problem.

You want to know what protocols are being used on your network. You'd like to monitor network traffic and sort traffic based on protocol. Which tool should you use? Throughput tester Packet sniffer Port scanner IDS IPS

Packet sniffer EXPLANATION A packet sniffer is special software that captures (records) frames that are transmitted on the network. Use a packet sniffer to: Identify the types of traffic on a network. View the exchange of packets between communicating devices. For example, you can capture frames related to DNS and view the exact exchange of packets for a specific name resolution request. Analyze packets sent to and from a specific device. View packet contents. Use a port scanner to identify protocol ports that are opened in a firewall or active on a device. A port scanner checks individual systems, while a packet sniffer watches traffic on the network. A throughput tester measures the amount of data that can be transferred through a network or processed by a device (such as the amount of data that can be retrieved from disk in a specific period of time). An intrusion detection system (IDS) is a special network device that can detect attacks and suspicious activity. A passive IDS monitors, logs, and detects security breaches, but takes no action to stop or prevent the attack. An active IDS (also called an intrusion protection system or IPS) performs the functions of an IDS, but can also react when security breaches occur.

You are concerned about attacks directed at the firewall on your network. You would like to examine the content of individual frames sent to the firewall. Which tool should you use? System log Throughput tester Packet sniffer Load tester Event log

Packet sniffer EXPLANATION A packet sniffer is special software that captures (records) frames that are transmitted on the network. Use a packet sniffer to: View packet contents. Identify the types of traffic on a network. View the exchange of packets between communicating devices. For example, you can capture frames related to DNS and view the exact exchange of packets for a specific name resolution request. Analyze packets sent to and from a specific device. A load tester simulates a load on a server or service. A throughput tester measures the amount of data that can be transferred through a network or processed by a device (such as the amount of data that can be retrieved from a disk in a specific period of time). System and event logs record what has happened on a device, but do not record individual frames or packets.

You've connected a cable certifier to an RJ45 wall jack and the output shown below is displayed on the device. What does this output indicate? (Select two.) 1 --------- 1 2 -------- 2 3 -------- 3 4 4 5 -------- 5 6 6 7 -------- 7 8 -------- 8 Pin 4 is shorted. Pin 4 is open. Pin 6 is shorted. Pins 4 and 6 are crossed-over. Pin 6 is open. Pins 4 and 6 are straight-through. The cable is functioning correctly.

Pin 4 is open. Pin 6 is open. EXPLANATION In this example, any connections displayed with no characters between the pin numbers are open connections. This problem is usually caused by: Poor connections between the wire and the RJ45 jack. Individual wires broken within the UTP cable. Output with x characters between pins indicates that they are shorted. Correctly functioning connections are displayed using - characters in the output of the cable certifier. Cross-over connections are displayed with lines between the crossed-over pins.

You've connected a cable certifier to an RJ45 wall jack. The output shown below is displayed on the device. What does this output indicate?. 1 XXXXXXXXX 1 2 XXXXXXXXX 2 3 -------------- 3 4 -------------- 4 5 -------------- 5 6 -------------- 6 7 -------------- 7 8 -------------- 8 Pins 1 and 2 are shorted. Pins 1 and 2 are crossed over. The cable is functioning correctly. Pins 1 and 2 are open.

Pins 1 and 2 are shorted. EXPLANATION In this example, the x characters on the lines for pins 1 and 2 indicate that these pins are shorted. This problem is usually (but not always) caused by poor connections between the wire and the RJ45 jack. Correctly functioning connections are displayed using - characters in the output of the cable certifier. Open connections are displayed with no characters between the pin numbers. Cross-over connections are displayed with lines between the crossed over pins.

Which of the following recommendations should you follow when placing access points to provide wireless access for users within your company building? Place access points in the basement. Place access points above where most clients are. Place access points near outside walls. Place multiple access points in the same area.

Place access points above where most clients are. EXPLANATION Follow a few guidelines for placing wireless access points: Devices often get better reception from access points that are above or below. If possible, place access points higher up to avoid interference problems caused by going through building foundations. For security reasons, do not place APs near outside walls. The signal will extend outside beyond the walls. Placing the AP in the center of the building decreases the range of the signals available outside of the building. When using multiple access points, place access points evenly through the area, taking care to minimize the overlap of the broadcast area while ensuring adequate coverage for all areas.

You decide to use a packet sniffer to identify the type of traffic sent to a router. You run the packet sniffing software on a device connected to the same hub that is connected to the router. When you run the software, you only see frames addressed to the workstation, not other devices. Which feature should you configure? Mirroring Promiscuous mode Bonding Spanning tree

Promiscuous mode EXPLANATION By default, a NIC only accepts frames addressed to itself. To enable the packet sniffer to capture frames sent to other devices, configure the NIC in promiscuous mode (sometimes called p-mode). In p-mode, the NIC processes every frame it sees. When devices are connected to a switch, the switch will only forward frames to the destination port. To see frames addressed to any device on any port, use port mirroring. In this scenario, the workstation and the router are connected with a hub, so the hub already sends all packets for all devices to all ports. Bonding logically groups two or more network adapters to be used at the same time for a single logical network connection. Spanning tree runs on a switch and ensures that there is only one active path between switches, allowing redundant paths.

You want to be able to identify traffic that is being generated and sent through the network by a specific application running on a device. Which tool should you use? Certifier Toner probe TDR Multimeter Protocol analyzer

Protocol analyzer EXPLANATION Use a protocol analyzer (also called a packet sniffer) to examine network traffic. You can capture or filter packets from a specific device or use a specific protocol. Use a time domain reflector (TDR) to measure the length of a cable or identify the location of a fault in the cable. A toner probe is two devices used together to trace the end of a wire from a known endpoint into the termination point in the wiring closet. A cable certifier is a multi-function tool that verifies or validates that a cable or an installation meets the requirements for a specific architecture implementation. A multimeter is a device that tests various electrical properties, such as voltage, amps, and ohms.

You are creating an Ethernet network for your company. The shipping department is located in a different building that is located 150 meters from the main wiring closet. You connect a single Cat 6a cable to connect the wiring closet to the shipping building. Which of the following should you include in your plan? Half-duplex Repeater Shielded twisted pair Spanning tree

Repeater EXPLANATION A repeater regenerates the signal and removes the unwanted effects caused by attenuation. Attenuation is the loss of signal strength from one end of a cable to the other. In this example, the distance from the wiring closet to the other building exceeds the 100-meter maximum for Ethernet, so a repeater is necessary to regenerate the signal. Use shielded twisted pair to protect against electromagnetic interference (EMI). Shielded cables have a metal foil that encloses all of the wires. Some cables might also include a drain wire, which is a bare wire in the middle of the wire bundle that helps to reduce EMI. More expensive cable might also use a metal foil around each pair of wires. The spanning tree protocol runs on switches to prevent switching loops by making only a single path between switches active at a single time. When using half-duplex communications, devices perform collision detection because the transmission medium is shared.

A user from the sales department calls to report that he is experiencing problems connecting to the sales file server. All users in the sales department connect to the sales server through a single Ethernet switch. No other users have reported problems connecting to the sales server. Which of the following troubleshooting actions are you most likely to perform first? Replace the network card in the sales server. Replace the network card in the user's computer. Reinstall the network card drivers on the sales server. Replace the Ethernet switch in the sales department.

Replace the network card in the user's computer. EXPLANATION In this scenario, you are most likely to replace the network card in the user's computer. As there is only one user experiencing a problem, you are unlikely to replace the network card in the server or replace the Ethernet switch. For the same reason, you are also unlikely to replace the network card drivers on the server. If more than one user were experiencing the problem, any of the options could be a valid troubleshooting step.

You are implementing a wireless network inside a local office. You require a wireless link to connect a laptop in the administrator's office directly to a system in the sales department. In the default configuration, the wireless AP uses a 360-dispersed RF wave design. After installation, the signal between the two systems is weak, as many obstacles interfere with the signal. Which of the following strategies could you try to increase signal strength? Increase the RF power on the isotropic antenna. Increase the RF setting on the client system. Increase the RF setting on the AP. Replace the omni-directional antenna with a directional antenna. Replace the directional antenna with an omni-directional antenna.

Replace the omni-directional antenna with a directional antenna. EXPLANATION A directional antenna is designed to create a narrow, focused signal in a particular direction. This focused signal provides greater signal strength between two points and increases the distance that the signal can travel. Because directional antennas provide a stronger point-to-point connection, they are better equipped to handle obstacles that may be in the way of the signal. The default antenna used with this configuration is an omni-directional antenna that disperses the RF wave in an equal 360-degree pattern. This antenna is commonly used to provide access to many clients in a radius.

You have a small network of devices connected together using a switch. You want to capture the traffic that is sent from Host A to Host B. On Host C, you install a packet sniffer that captures network traffic. After running the packet sniffer, you cannot find any captured packets between Host A and Host B. What should you do? Manually set the MAC address of Host C to the MAC address of Host A. Run the packet sniffer application on Host B. Connect hosts A and B together on the same switch port through a hub. Configure the default gateway address on hosts A and B with the IP address of Host C.

Run the packet sniffer application on Host B. EXPLANATION You need to run the packet sniffing software on either Host A or Host B. Network traffic is sent through a switch to only the destination device. In this scenario, Host C will only receive broadcast traffic and traffic addressed to its own MAC address. Alternatively, you could put Host C on the same switch port as either Host A or Host B using a hub. When connected with a hub, all devices connected to the hub will be able to see the traffic sent to all other devices connected to the hub. Changing the MAC address on Host C would cause a conflict with duplicate addresses being used. Setting the default gateway would not affect the path of packets on the LAN. The default gateway is only used for traffic that goes outside of the current subnet.

You have physically added a wireless access point to your network and installed a wireless networking card in two laptops running Windows. Neither laptop can find the network, and you have come to the conclusion that you must manually configure the wireless access point (AP). Which of the following values uniquely identifies the network AP? WEP Channel PS SSID

SSID EXPLANATION The SSID (service set identifier) identifies the wireless network. All PCs and access points in a LAN share the same SSID. WEP (Wired equivalent privacy) is used to add a layer of security to the transmission, while the channel identifies the frequency that the card and AP will communicate on.

Mobile devices in your organization use the access points shown in the figure below to connect to your wireless network. Recently, a catastrophic early morning power surge occurred. It was followed by an outage that lasted longer than your backup equipment could supply temporary power. After you powered the equipment back on, everything initially appeared to work correctly. However, ever since this event, some mobile users report that wireless network connections sometimes get dropped or perform very poorly. What should you do? (Select two.) Configure each access point to use 802.1x authentication. Set access point B to use 802.11n wireless networking. Set the channel used by access point C to 7. Set the channel used by access point B to 11. Set the channel used by access point A to 5. Configure each access point to use a different SSID. Set the channel used by access point B to 8. Set access points A and C to use 802.11b wireless networking.

Set access point B to use 802.11n wireless networking. Set the channel used by access point B to 11. EXPLANATION During the power surge and/or power outage, some of the configuration settings on access point B were lost or reset to default values. To fix the issues users are experiencing, you need to: Set access point B to use 802.11n wireless networking. This will rectify the poor performance users are experiencing while accessing the wireless network through access point B. Set the channel used by access point B to 11. 2.4 GHz channels overlap. In this scenario, the channel used by access point B (4) overlaps with the channels used by access points A (1) and C (6). This will rectify the dropped connections users are experiencing. Channels 5, 7, and 8 overlap with channel 6, so setting any access point to these channels will cause a conflict with access point C. Using the same SSID on all access points allows users to roam about the facility and stay connected to the same wireless network. While using 802.1x authentication would make the wireless network more secure, it will not address the issues users are experiencing. Configuring access points A and C to use 802.11b will cause all users to experience poor network performance.

You use Cat5e twisted pair cable on your network. Cables are routed through walls and the ceiling. A user puts a screw in the wall to hang a picture and pierces the cable so that a signal sent on pin 1 arrives on the cable connected to pin 7. Which term describes this condition? Short circuit Attenuation Open circuit Split pair Crosstalk

Short circuit EXPLANATION An electrical short occurs when electrical signals take a path other than the intended path. In the case of twisted pair wiring, a short means that a signal sent on one wire might arrive on a different wire. Shorts are caused by worn wire jackets, crushed wires that touch, and pierced wire that touches metal. If an open circuit is a cut in the wire that prevents the original signal from reaching the end of the wire, you will have a short. If you have a short, the signal travels a different path. If you have an open circuit, the signal does not travel anywhere (electricity cannot flow because the path is disconnected). Crosstalk is interference that is caused by signals within the twisted pairs of wires. Attenuation is the loss of signal strength from one end of a cable to the other caused by distance. A split pair condition is where a single wire in two different pairs is reversed at both ends. For example, instead of matching the green and green/white wires in pins 1 and 2, you swap the solid green wire with the solid brown wire.

Users report that the internet is no longer accessible. You suspect that the line connecting your building to the internet is not working properly. Which of the following allows the service provider to remotely test the local loop? Horizontal cross connect Loopback plug Demarc extension Smartjack Demarc

Smartjack EXPLANATION A smartjack is a special loopback plug installed at the demarcation point for a WAN service. Technicians at the central office can send diagnostic commands to the smart plug to test connectivity between the central office and the demarc. A smartjack is similar to a loopback plug; however, the loopback plug must be manually inserted into a jack to test the line, while the smartjack is a special plug that includes loopback support and can be used to test the local loop remotely. Your provider's technicians can use a smartjack to diagnose the local loop without visiting your location. The demarcation point (demarc) is the line that marks the boundary between the telco equipment and the private network or telephone system. A demarc extension extends the demarcation point from its original location to another location within the building. A horizontal cross connect connects wiring closets on the same floor.

When troubleshooting network issues, it's important to carry out tasks in a specific order. Drag the trouble shooting task on the left to the correct step on the right. Drag: Establish a plan of action. Implement the solution or escalate. Test the theory to determine the cause. Establish a theory of probable cause. Identify the problem. Document findings, actions, and outcomes. Verify full system functionality. Drop: Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7

Step 1 - Identify the problem. Step 2 - Establish a theory of probable cause. Step 3 - Test the theory to determine the cause. Step 4 - Establish a plan of action. Step 5 - Implement the solution or escalate. Step 6 - Verify full system functionality. Step 7 - Document findings, actions, and outcomes. EXPLANATION The following is a general approach to network troubleshooting: Identify the problem. Establish a theory of probable cause. Test the theory to determine the cause. Establish a plan of action to resolve the problem and identify potential effects. Implement the solution or escalate as necessary. Verify full system functionality and, if applicable, implement preventative measures. Document findings, actions, and outc

You have been asked to document the wiring in your building. You would like to identify the length of each Cat5 cable to verify that it meets Ethernet standards. You need to identify the length of the cables, but most cables run through walls and ceilings, making them difficult to trace. Which tool should you use? Butt set TDR Smartjack Toner probe OTDR

TDR EXPLANATION A TDR is a special device that sends electrical pulses on a wire in order to discover information about the cable. The TDR measures impedance discontinuities; the echo received on the same wire in response to a signal on the wire. The results of this test can be used to: Estimate the length of a wire. Measure the cable impedance. Identify the locations of splices and connectors on the wire. Identify shorts, open circuits, and the location of the fault. An optical time domain reflector (OTDR) performs the same function for fiber optic cables using light waves. A toner probe is two devices used to trace the end of a wire from a known endpoint into the termination point in the wiring closet. A butt set (also called a lineman's handset) is a device used to test analog telephone installations. The butt set includes an earpiece, mouthpiece, dialing interface, and various connectors. A smartjack is a special loopback plug installed at the demarcation point for a WAN service. Technicians at the central office can send diagnostic commands to the smart plug to test connectivity between the central office and the demarc.

You are a network administrator for your company. A user calls and tells you that after stepping on the network cable in her office, that she can no longer access the network. You go to the office and see that one of the user's stiletto heels has broken and exposed some of the wires in the Cat 5 network cable. You make another cable and attach it from the wall plate to the user's computer. What should you do next in your troubleshooting strategy? Establish what has changed. Test the solution. Document the solution. Recognize the potential effects of the solution.

Test the solution. EXPLANATION After you implement a solution, you should always test it. Sometimes more than one problem exists, or your solution may not have solved the problem. In this example, you may have incorrectly set the wires in the network cable you just made, or the user may have jarred the computer and damaged the NIC when she stepped on the cable.

Your organization recently opened a branch office. You contracted with a WAN service provider to connect the branch office network to your home office network. Recently, your CEO conducted a video conference with the employees at the branch office. The employees complained that the video was choppy and the audio was frequently out of sync with the video. What is the most likely cause of this poor WAN performance? There is a data link encapsulation protocol mismatch between the WAN interfaces on both ends of the link. There is an authentication misconfiguration issue between the WAN interfaces on both ends of the link. There is an IP address misconfiguration issue between the WAN interfaces on both ends of the link. The WAN interface on the router at the branch office has been disabled. The WAN provider is throttling bandwidth on the link.

The WAN provider is throttling bandwidth on the link. EXPLANATION In this scenario, its possible that the WAN service provider is the cause of the problem. You should check the contract with the service provider to make sure they aren't throttling the bandwidth of the WAN link. It's not uncommon for service providers to impose bandwidth or utilization caps that could be hampering communications. Because connectivity exists between the home and branch office networks in this scenario, the following are very unlikely to be the cause of the problem: A disabled WAN interface A protocol mismatch An authentication mismatch An IP address misconfiguration

A user on your network has been moved to another office down the hall. After the move, she calls you complaining that she has only occasional network access through her wireless connection. Which of the following is most likely the cause of the problem? The client has incorrect WEP settings. The client system has moved too far away from the access point. An SSID mismatch between the client and the server. An SSID mismatch between the client and the WAP. The encryption level has been erroneously set back to the default setting.

The client system has moved too far away from the access point. EXPLANATION In this case, the wireless client system has had no problems accessing the wireless access point until she moves to the new office. In some cases, moving a system will cause signal loss either from the increased distance away from the WAP or from unexpected interference by such things as concrete walls or steel doors. There are several ways to correct the problem, including reducing the physical distance to the client, using a wireless amplifier, upgrading the antennae on the wireless devices, or adding another WAP to the infrastructure. Because the client could previously access the WAP and still has occasional access, it is likely that the move was the cause of the problem and not any configuration setting on the client system.

A user calls to report that she is experiencing intermittent problems while accessing the wireless network from her laptop computer. While talking to her, you discover that she is trying to work from the coffee room two floors above the floor where she normally works. What is the most likely cause of her connectivity problem? The user has not yet logged off and back on to the network while at her new location. The user is out of the effective range of the wireless access point on her floor. The user has not yet rebooted her laptop computer while at her new location. The wireless network access point on the user's normal floor has failed. The user needs a new IP address because she is working on a different floor.

The user is out of the effective range of the wireless access point on her floor. EXPLANATION Because the user is only experiencing intermittent problems, the most likely cause is that she is out of the effective range of the wireless network access point. All of the other answers listed may be appropriate if the user was unable to connect to the network at all. However, as the user is experiencing only intermittent problems, none of the other answers is likely to cure the problem.

Your organization recently opened a branch office in a remote area. Because of its location, traditional WAN connectivity was not available, so you contracted with a satellite provider to connect the branch office network to your home office network. Recently, your CEO conducted a video conference with the employees at the branch office. The employees complained that the video was choppy and the audio was frequently out of sync with the video. What is the most likely cause of this poor WAN performance? There is an IP address misconfiguration issue between the WAN interfaces on both ends of the link. There is latency on the WAN link. There is a data link encapsulation protocol mismatch between the WAN interfaces on both ends of the link. The WAN interface on the router at the branch office has been disabled. There is an authentication misconfiguration issue between the WAN interfaces on both ends of the link.

There is latency on the WAN link. EXPLANATION In this scenario, its very likely that the satellite link itself is the cause of the problem. Because the radio signals used by satellite links must travel thousands of miles into space and back, several milliseconds of latency are introduced. For some types of network communications, such as saving a file or sending an email, this latency is not a problem. However, for time-sensitive communications such as a video conference, the latency inherent in the satellite link can cause poor network performance. Because connectivity exists between the home and branch office networks, the following are very unlikely to be the cause of the problem: A disabled WAN interface A protocol mismatch An authentication mismatch An IP address misconfiguration

You have a WAN link that connects two sites. The WAN link is supposed to provide 1.5 Mbps of bandwidth. You want to perform a test to see the actual bandwidth of the link. Which tool should you use? Throughput tester Packet sniffer Load tester Baseline

Throughput tester EXPLANATION A throughput tester measures the amount of data that can be transferred through a network or processed by a device (such as the amount of data that can be retrieved from disk in a specific period of time). On a network, a throughput tester sends a specific amount of data through the network and measures the time it takes to transfer that data, arriving at a measure of the actual bandwidth. Use a throughput tester to validate the bandwidth on your network and identify when the bandwidth is significantly below what it should be. A baseline would tell you the average amount of data sent on the WAN link, but would not tell you the actual capacity or bandwidth for that link. A load tester simulates a load on a server or service. A packet sniffer is special software that captures (records) frames that are transmitted on the network.

While configuring a new 802.11g wireless network, you discover another wireless network within range that uses the same channel ID that you intend to use. Which of the following strategies are you most likely to adopt in order to avoid a conflict between the networks? Use the same channel ID, but configure your wireless network to use WEP. Use 802.11b instead of 802.11g. Use a different channel ID. Use the same channel ID, but configure a different SSID.

Use a different channel ID. EXPLANATION Overlapping wireless networks should use different channels to ensure that they do not conflict with each other. Even though you should use a different SSID anyway, you would also need to configure a different channel for each of the wireless networks. Using 802.11b instead of 802.11g would not avoid a conflict between the networks and would limit the speed of the wireless network to 11Mbps as opposed to 54Mbps available with 802.11g. Using Wired Equivalent Privacy (WEP) is a prudent security measure; however, it does not prevent the conflicts that can occur with overlapping wireless networks that use the same channel ID.

You have just been hired as a network administrator. A user has just changed offices and needs you to activate the network and telephone connections in his office. However, the wiring at the punch down block is labeled poorly, and you are unable to tell which wires go to the user's office. What should you do? Install new wiring from the punch down block to the user's office. Use a tone generator to locate the correct wiring. Use a punch down tool to locate the correct wiring. Use a media tester to locate the correct wiring.

Use a tone generator to locate the correct wiring. EXPLANATION A tone generator allows you to create a tone at on end of a wire and find the other end by testing all connections at the location of the other end of the wire.

Which TCP/IP utility gives you the following output? Interface: on Interface 0x2 arp -a nbtstat -c netstat -a ipconfig

arp -a EXPLANATION The arp -a command shows the current entries in the computer's ARP cache.

Consider the following output. ;; res options: init recurs defnam dnsrch ;;got answer: ;;->>HEADER<<-opcode:QUERY, status; NOERROR,id:4 ;;flags: qr rd ra; QUERY:1, ANSWER:1, AUTHORITY:2, ADDITIONAL:0 ;;QUERY SECTION:;; westsim111.com, type = A, class = IN ;;ANSWER SECTION: westsim111.com. 7h33m IN A 76.141.43.129 ;;AUTHORITY SECTION: westsim111.com. 7h33m IN NS dns1.deriatct111.com. westsim111.com. 7h33m IN NS dns2.deriatct222.com. ;;Total query time: 78 msec ;;FROM: localhost.localdomain to SERVER: default -- 202.64.49.150 ;;WHEN: Tue Feb 16 23:21:24 2005 ;;MSG SIZE sent: 30 rcvd: 103 Which of the following utilities produced this output? ping dig nslookup nbtstat

dig EXPLANATION The output shown is from the dig command run on a Linux system. Although nslookup and dig provide some of the same information, you can tell this output came from dig because dig produces significantly more detail in its default usage. Use nbtstat to view information on the NetBIOS over TCP/IP (NetBT) name resolutions that have been performed. Use ping to test connectivity between systems on a network.

You need to perform a reverse lookup of the 10.0.0.3 IP address. Which command can you use to accomplish this? (Select two. Each response is a complete solution.) ipconfig /dnslookup 10.0.0.3 arp 10.0.0.3 dig -x 10.0.0.3 nbtstat -a 10.0.0.3 nslookup 10.0.0.3

dig -x 10.0.0.3 nslookup 10.0.0.3 EXPLANATION To perform a reverse lookup of the 10.0.0.3 IP address, use either of the following commands: dig -x 10.0.0.3 nslookup 10.0.0.3 The ipconfig command is used to perform a forward or reverse DNS lookup. The arp 10.0.0.3 command displays the MAC address of the network host with an IP address of 10.0.0.3. The nbtstat -a 10.0.0.3 command displays the NETBIOS name of the host assigned an IP address of 10.0.0.3.

You are troubleshooting a connectivity problem on a Linux server. You are able to connect to another system on the local network, but are not able to connect to a server on a remote network. You suspect that the default gateway information for the system may be configured incorrectly. Which of the following commands would you use to view the default gateway information on the Linux server? ipconfig winipcfg dig ifconfig

ifconfig EXPLANATION Use the ifconfig command on systems running Linux to view information on the TCP/IP configuration of network adapters. Use ipconfig and winipcfg to view network configuration information on Windows systems. Use the dig command on Linux and Unix systems to query Domain Name Service (DNS) servers.

Which TCP/IP utility gives you the following output? Ethernet adapter Local Area Connection: ipconfig netstat -a winipcfg arp -a

ipconfig EXPLANATION The ipconfig command shows the computer's TCP/IP configuration information. winipcfg also shows the TCP/IP configuration, but in a Windows graphical format.

You have been called in to troubleshoot a connectivity problem on a newly installed Windows Server 2016 system. The system is operating satisfactorily and is able to communicate with other systems on the local network. However it is unable to access any systems on other segments of the corporate network. You suspect that the default gateway parameter for the system has not been configured, or may be configured incorrectly. Which of the following utilities are you most likely to use to view the default gateway information for the system? netstat winipcfg ifconfig ipconfig

ipconfig EXPLANATION Use the ipconfig utility to view the TCP/IP configuration of a Windows Server 2003 system. The information displayed by ipconfig includes default gateway information. Use winipcfg to view the TCP/IP configurations on earlier versions of Windows including Windows 98 and Me. It is not supported by Windows Server 2003. Use the ifconfig command to view the TCP/IP configuration on a Linux, Unix or Macintosh system. Use the netstat command to view statistics on TCP connections.

You administer a NetBIOS-based network that uses the TCP/IP protocol. You are trying to troubleshoot a computer that is unable to contact a server by its NetBIOS name. Which command can you use to check the connection? nbtstat nbname netstat netbt

nbtstat EXPLANATION Use nbtstat to troubleshoot NetBIOS name resolution problems. The command shows which NetBIOS names the server uses, and which NetBIOS names the client knows about.

Which TCP/IP utility gives you the following output? Local Area Connection: Node IpAddress: [192.168.1.111] Scope Id: [] Net BIOS Remote Cache Name Table Name Type Host Address Life [sec] NTINE.ES <54> UNIQUE 192.168.1.23 395 NTINE <20> UNIQUE 192.168.1.23 45 AUDIO <00> UNIQUE 192.168.1.168 585 netstat -r nbtstat -c netstat -a arp -a

nbtstat -c EXPLANATION nbtstat -c shows you the resolved NetBIOS name cache for a computer. In other words, these are the NetBIOS name-to-IP address mappings for known remote computers.

Examine the following output: Active Connections Proto Local Address Foreign Address State TCP SERVER1:1036 localhost:4832 TIME_WAIT TCP SERVER1:4798 localhost:1032 TIME_WAIT TCP SERVER1:1258 pool-141-150-16-231.mad.east.ttr:24076 CLOSE_WAIT TCP SERVER1:2150 cpe-66-67-225-118.roc.res.rr.com:14100 ESTABLISHED TCP SERVER1:268 C872c-032.cpe.net.cale.rers.com:46360 ESTABLISHED TCP SERVER1:2995 ip68-97-96-186.ok.ok.cox.net:23135 ESTABLISHED Which of the following utilities produced this output? nslookup ifconfig netstat dig

netstat EXPLANATION The output shown is produced by the netstat command. netstat reports the TCP/IP ports open on the local system, as well as identifying the protocol and remote host connected to that port. This information can be very useful when looking for security weaknesses, as a TCP/IP port that is open to traffic unnecessarily represents a security risk. ifconfig is a tool used on Unix, Linux and Macintosh systems to view the configuration of network interfaces, including TCP/IP network settings. The dig command allows you to perform manual DNS lookups from a Linux or Unix system. This can be very useful when troubleshooting name resolution issues. In addition to Linux and Unix systems, nslookup allows you to perform manual DNS lookups from a Windows system.

Your computer is sharing information with a remote computer using the TCP/IP protocol. Suddenly, the connection stops working and appears to hang. Which command can you use to check the connection? ipconfig ping netstat arp nbtstat

netstat EXPLANATION Use the netstat command to check the status of a TCP connection.

Which TCP/IP utility gives you the following output? Route Table netstat -a nbtstat -c netstat -r arp -a

netstat -r EXPLANATION netstat -r shows you the computer's route table.

Which command displays network activity statistics for TCP, UDP, and IP? telnet nbtstat -s netstat -s ping -s nslookup

netstat -s EXPLANATION Netstat -s displays network activity statistics for TCP, UDP, and IP.

Examine the following output: Server: to.xct.mirrorxhq.net Address: 209.53.4.130 Name: westxsim.com Address: 64.78.193.84 Which of the following utilities produced this output? nslookup tracert netstat ipconfig

nslookup EXPLANATION The output is from the nslookup command on a Windows Server system. nslookup is a tool that allows you to send manual DNS resolution requests to a DNS server. The output displays the IP address and host name of the DNS server that performed the resolution, and the IP address and host name of the target specified for resolution. nslookup can be a useful tool when troubleshooting DNS name resolution problems. The ipconfig utility is used on a Windows system to view the TCP/IP configuration of network interfaces. netstat is used to view protocol connections that have been established by the system, as well as what incoming TCP/IP ports are in use by the system. tracert is a tool used to view information on the route a packet takes as it traverses the network to a remote host.

You are troubleshooting a network connectivity issue on a Unix system. You are able to connect to remote systems by using their IP address, but unable to connect using the host name. You check the TCP/IP configuration and note that a DNS server IP address is configured. You decide to run some manual resolution queries to ensure that the communication between the Unix system and the DNS server are working correctly. Which utilities can you use to do this? (Choose two.) traceroute tracert nslookup dig

nslookup dig EXPLANATION The dig and nslookup commands allow you to perform manual DNS lookups from a Linux or Unix system. This can be very useful when you are troubleshooting name resolution issues. Use tracert and traceroute to track the route that a packet takes as it crosses a network. You would not typically use these commands to troubleshoot a name resolution problem, though they may be useful if you are unable to connect to the DNS server

You work in an office that uses Linux servers and Windows servers. The network uses the TCP/IP protocol. You are sitting at a workstation that uses Windows 10. An application you are using is unable to contact a Windows server named FileSrv2. Which command can you use to determine whether your computer can still contact the server? arp tracert ping nwlookup

ping EXPLANATION On a TCP/IP-based network, you can use the ping command to check connectivity between a source and destination computer.

Which TCP/IP utility gives you the following output? Reply from............. ipconfig ping ifconfig arp -a

ping EXPLANATION The output of the ping command shows you the results of four echo request/reply contacts with a destination host.

Examine the following output. Reply from 64.78.193.84: bytes=32 time=86ms TTL=115 Reply from 64.78.193.84: bytes=32 time=43ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=47ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=73ms TTL=115 Reply from 64.78.193.84: bytes=32 time=46ms TTL=115 Which of the following utilities produced this output? tracert nslookup ping ifconfig

ping EXPLANATION The output shown was produced by the ping utility. Specifically, the information output was created using theping -t command. The -t switch causes packets to be sent to the remote host continuously until stopped manually. ping is a useful tool for testing connectivity between devices on a network. Using the -t switch with ping can be useful in determining whether the network is congested, as such a condition will cause sporadic failures in the ping stream. tracert is similar to ping in that it tests connectivity between two hosts on the network. The difference is that tracert reports information on all intermediate devices between the host system and the target system. ping, on the other hand, does not report information on intermediate devices. nslookup is a tool provided on Linux, Unix and Windows systems that allows manual name resolution requests to be made to a DNS server. This can be useful when troubleshooting name resolution problems. ifconfig is a tool used on Unix, Linux and Macintosh systems to view the configuration of network interfaces, including TCP/IP network settings.

Your office has both Windows and Linux computers. You want to be able to view the address of the default gateway that a computer is using. Which of the following utilities could you use? (Select two.) dig route netstat ipconfig host

route ipconfig EXPLANATION Use the ipconfig command on Windows or the route command on Linux to view the default gateway. The ipconfig command will also show the IP configuration for network interfaces, including the IP address, subnet mask, and DNS server addresses being used by a Windows computer. Use host and dig to get the IP address of a host name. Use netstat to view IP-related statistics, including incoming and outgoing connections and active sessions, ports, and sockets.

You are troubleshooting physical layer issues with the Gi0/1 interface in a router. You need to view and analyze the number of collisions detected on the interface. Which command should you use? show interfaces gi0/1 show controllers gi0/1 show interfaces gi0/1 description show interfaces gi0/1 status

show interfaces gi0/1 EXPLANATION The show interfaces gi0/1 command displays statistics about the Gi0/1 interface, including the number of collisions and late collisions. The show interfaces gi0/1 status command displays summary information about the interface status. The output displays the port, name, status, VLAN assignment, duplex configuration, interface speed, and link type. The show interfaces gi0/1 description command displays the line and protocol status of the interface. The show controllers command is used to display configuration parameters for serial interfaces (not Ethernet interfaces), such as the type of serial cable and which end of the cable is connected to the device (DCE or DTE).

You are troubleshooting physical layer issues with the Gi0/1 interface in a router. You suspect that a duplex mismatch error has occurred, and you need to determine the duplex settings configured on the interface. Which commands could you use? (Choose two. Each response is a complete solution.) show interfaces gi0/1 show interfaces counters show interfaces gi0/1 description show interfaces gi0/1 status show controllers gi0/1

show interfaces gi0/1 show interfaces gi0/1 status EXPLANATION Both the show interfaces gi0/1 command and the show interfaces gi0/1 status command display configuration information for the Gi0/1 interface, including the duplex configuration. Using this information, you can identify duplex mismatch errors. The show interfaces gi0/1 description command displays the line and protocol status of the interface. The show controllers command is used to display configuration parameters for serial interfaces (not Ethernet interfaces), such as the type of serial cable and which end of the cable is connected to the device (DCE or DTE). The show interfaces counters command displays the traffic on the physical interface.

Each of the following are tools used to check the health of a network. Which of these is typically used for managing and sending messages from one computer system to another? Load tester Protocol analyzer syslog Packet sniffer

syslog EXPLANATION The syslog standard is used for managing and sending log messages from one computer system to another. It can analyze messages and notify administrators of problems or performance. A packet sniffer is special software that captures (records) frames that are transmitted on the network. A protocol analyzer is a special type of packet sniffer that captures transmitted frames. A load tester simulates a load on a server or service.

While working on a Linux server, you are unable to connect to Windows Server 2016 system across the Internet. You are able to ping the default gateway on your own network, so you suspect that the problem lies outside of the local network. Which utility would you use to track the route a packet takes as it crosses the network? dig traceroute ipconfig nslookup tracert ifconfig

traceroute EXPLANATION traceroute is a Linux utility that allows you to track the route of a packet as it traverses the network. The traceroute utility is used on Linux systems, while tracert is used on Windows systems. ipconfig and ifconfig are utilities used to obtain TCP/IP configuration on Windows and Linux systems respectively. nslookup and dig are utilities used to perform manual DNS lookups on Windows and Linux systems respectively.