Question 1

You are trying to find out why a network card will not connect to the network. Which of the following should you check first?
A)Driver
B)Link light
C)Processor
D)RJ-45 cable

Accepted Answer

If the network card will not connect to the network, you should check the link light first.
Key Takeaway: When it comes to network cards, the first thing you want to check is the link light on the back of the computer to verify that there is an actual connection to the network. If the link light does not glow, run the loopback test. If the link light does glow, then you should proceed with troubleshooting the next phases of the network.

Question 2

A user calls in and reports that the Wi-Fi connection is disconnected when the house telephone rings. Which of the following could cause this issue?
A)The cordless phones are plugged into same outlet as the router.
B)The 5.8 GHz cordless phone is interfering with the wireless network.
C)The 2.4 GHz cordless phone is interfering with the wireless network.
D)The laptop NIC is faulty.

Accepted Answer

In this case, the 2.4 GHz cordless phone is interfering with the wireless network.
Key Takeaway: Cordless phones are used in the 2.4 GHz range. Most of the time, the wireless connection and the cordless phones are operating on close channels and physical proximities. Hence, they change the operating frequency range of the wireless network.

Question 3

Jack is a network administrator at his organization. Last night he accidentally messed up the connections running to the server. Today all users have been complaining about not having Internet connectivity and IP addresses in the 169.254.xxx.xxx series. What should Jack check first?
A)DHCP server
B)DNS server
C)Client NIC
D)Internet Explorer

Accepted Answer

Jack should check the DHCP server or configurations. The 169.254 series of IP addresses is an APIPA-an IP address assigned when the computer is not able to obtain an IP address through DHCP.
Key Takeaway: The automatic private IP addressing (or APIPA) feature automatically assigns a 169.254.xxx.xxx address if the system does not obtain an IP address from the DHCP server at boot. When DHCP is not available, and a client workstation whose IP address is assigned by DHCP attempts to get its IP settings, APIPA allocates addresses in the private range 169.254.1.0 to 169.254.254.255, exclusive of the first and last 255 addresses. Clients verify their address is unique on the LAN by querying the other hosts using ARP and verifying that the address is not already assigned on the local network by another clients use of APIPA. When DHCP is available again, clients should update their addresses automatically, although sometimes they have to be forced to renew their DHCP settings manually. Any devices configured with APIPA use the default network mask 255.255.0.0 and are therefore all on the same subnet. This ensures that all devices configured in this manner on the same LAN can communicate with each other. APIPA is enabled on all DHCP clients in Windows by default, but can be disabled for the whole client or by individual network adapter.

Question 4

In a scenario where two computers have been assigned the same IP address, which of the following could be the result?
A)Both computers will connect to the network.
B)Both computers will be able to connect to the local network, but not to the Internet.
C)Both computers will not be able to connect to the local network or the Internet.
D)The computer which was first assigned the IP address will be able to connect, the other will not.

Accepted Answer

The computer which was first assigned the IP address will be able to connect, the other will not. As soon as an IP address is assigned to a host, the address is locked. If a DHCP is used on both computers, then the second PC will never get the same IP address. However if the second PC tries to statically assign the same IP, then IP conflict error arises.
Key Takeaway: if a second system tries to manually assign an IP address that is already in use, the error "There is an IP address conflict with another computer on the network" pops up. These problems typically arise when a computer on the network is assigned an automatic/static IP and the other computer is assigned a manual IP.

Question 5

Jack is a network administrator at his organization. The computers in the finance department are connected to a hub. The employees in the finance department are complaining about very slow intermittent network and Internet access. On inspection, Jack finds that the activity LED on the hub sometimes turns orange. What is the most likely cause of the issue?
A)One of the employee's cables is disconnected from the hub.
B)Collisions are occurring on the network due to electrical interference.
C)The NIC drivers on the employees' systems are outdated.
D)The system resources on the employees' computers are very low.

Accepted Answer

The orange light on the hub is due to the collisions on the network.
Key Takeaway: Many times EMI causes interference on the network. Hubs have limited bandwidth if many users are connected simultaneously, sometimes leading to collisions. If there are collisions on the network, the activity LED turns orange. Under normal circumstances, the LED remains green.

Question 6

Which of the following parameters is not required if you want to communicate with a system on the same LAN?
A)IP address
B)Subnet mask
C)MAC address
D)Default gateway

Accepted Answer

You need not configure the default gateway if you are configuring a system to communicate with a system on the same LAN.
Key Takeaway: The default gateway is the router that the host uses to send data to hosts on other networks. In this case, you do not need to set the default gateway as all of the data is staying on the same network.

Question 7

John is working as a network administrator in his organization. A user is unable to connect to the network. All other users on that switch are able to connect successfully to the network. Which of the following could be a probable cause of this issue?
A)The DNS server is down.
B)Wrong subnet mask on the switch
C)Switching loop is occurring on the switch
D)Misconfigured port on the switch

Accepted Answer

Only one user on the network is facing this issue, so it can be concluded that the network is fine. This issue is associated with a part of the network that is related to the affected user only.
Key Takeaway: Of the options given here, if a DNS server issue, subnet issue, or switching loop issue occurs, the entire network would be affected. Hence, a port on the switch must be misconfigured, a cable is unplugged or otherwise shorted out, or the NIC on the computer is misconfigured, has a corrupt driver, or is faulty.

Question 8

After connecting a PC to an available port on a switch, you find that the PC cannot access any of the resources on the LAN. No other PCs connected to the switch appear to be having any issues. What is the most likely cause of this problem?
A)The host MAC address is configured incorrectly.
B)The host switch port is assigned to the incorrect VLAN.
C)A STP instance for the new host has not been initialized.
D)The router lacks a routing table entry for the new host.

Accepted Answer

While a cabling issue, NIC misconfiguration, or NIC malfunction are the most likely culprits of this behavior, in this case, a VLAN configuration is used to segment the network, and the others are not listed, so the host switch port is most likely assigned to an incorrect VLAN.
Key Takeaway: VLANs mostly use a port-based membership. In this case, the VLAN is defined based on the ports that belong to the VLAN. The main disadvantage of this method is that it does not allow for user mobility. If a user moves to a different location away from the assigned bridge, the network manager must reconfigure the VLAN. Even if the PC is not moved, it is important to connect the PC to the correct VLAN port. If connected incorrectly, the PC will not be able to connect to any resources on the network.

Question 9

If a connection that usually takes 9 hops to reach a particular web server is now taking 13 hops to reach it, how would it affect the connection?
A)Hops do not affect the speed of the connection.
B)The connection will be faster than before.
C)The connection will be fractionally slower than before.
D)It cannot be determined if the connection will be affected.

Accepted Answer

Even though there is an increase in the number of hops, it cannot be assumed that the time taken has been more than before. Therefore, one cannot determine if the connection would get faster or slower.
Key Takeaway: There may be a situation where 9 hops may take 10 ms in total. In the second case, the hop count may have increased to 13, but it does not mean that these hops have taken more than 10 ms. Therefore, it cannot be determined how an increase in the number of hops affects the connection. One can only be sure after having a look at the trace route command results.

Question 10

You are working as a network administrator in your organization. A user complains that he is not able to print from a network printer attached to the network. When you try to ping the printer with an IP address, it gives a successful reply, but a host name ping fails. What could be the most likely cause?
A)Print server is down
B)DHCP server is down
C)Printer is too far from the user
D)DNS server is down

Accepted Answer

If an IP address ping is working and the host name ping fails, then the DNS server is down.
Key Takeaway: If the DHCP server were down, the ping request would either not work at all or work both times. If the print server were down, then the ping request would not work.

Question 11

Jack is planning to implement a fault tolerant mechanism on his company's web server. This is to avoid having to replace a failed drive and restore data without blocking data requests from many of the company's valuable customers. Which of these features should he implement on the web server?
A)Incremental backup
B)RAID 0
C)UPS
D)RAID 1

Accepted Answer

He should implement RAID 1 or data mirroring to be able to replace a failed hard drive on the fly.
Key Takeaway: RAID 1 creates an exact copy (or mirror) of a set of data on two or more disks. This is useful when read-performance or reliability is more important than data storage capacity. A drive has its data duplicated on two different drives using either a hardware RAID controller or software. If either of the drives fail, the other continues to function as a single drive until the failed drive is replaced. It is popular for those who require fault tolerance and don't need top-notch read performance.

Question 12

Your 802.11n capable SOHO router is providing 11Mbps speeds to the network. What is most likely the issue?
A)The SOHO router is using a WEP key for security.
B)The SOHO router does not have the latest firmware upgrade.
C)The SOHO router is operating in mixed mode.
D)There is no issue.

Accepted Answer

Since the 802.11n SOHO router is operating in mixed mode, it is likely that is the culprit for providing 11Mbps speeds to the network.
Key Takeaway - 802.11n capable SOHO routers should be capable of speeds of up to 600Mbps, but when operating in Mixed Mode, this speed may not be as efficient as you like. If you have other devices, such as a Wii, which operate on older Wi-Fi standards like 802.11b, you have no choice but to run the router in mixed mode. A Firmware upgrade could possibly speed things up, but this shouldn't explain the great reduction in speed.

Question 13

You notice that a device with a manual IP address cannot communicate with other devices on the network. The network has the address 192.168.4.x with a subnet mask of 255.255.255.0. The IP address of the non-communicative station is 192.168.4.12/26. What is the most likely reason this system cannot communicate?
A)It has the wrong subnet mask
B)It is using a private IP address
C)Its IP address is wrong
D)The TCP/IP stack is corrupt

Accepted Answer

The subnet mask is wrong, and the device will not be able to communicate with the rest of the network.
Key Takeaway: The subnet mask lets us know what part of the address refers to the network ID. In this case, the malfunctioning computer is using an additional two bits to reference the network ID. Therefore, even though the IP address looks right, this machine is logically on a different network due to it using the wrong subnet mask.

Question 14

Which command would you use on the Windows command line to ping a system continuously until you press ? A)Ping -n a B)Pin -n c C)Ping -n D)Ping -t

Accepted Answer

Ping -t will continuously ping a system until interrupted by the user.
Key Takeaway: At the windows command line, the ping command can be made to continuously send the ICMP packets by using the -t switch. On *nix systems no switch is needed for this behavior to occur as the Unix ping utility continuously pings by default.

Question 15

Samuel replaces a 10BaseT NIC on a workstation with a 10/100BaseT card. He now does not get a link light on the NIC even though he has plugged it in to multiple ports on the switch. He notices from the documentation that this cut rate card has no auto negotiation mode. What is the most likely problem causing the loss of connectivity?
A)It cannot bind TCP/IP to it
B)The card is malfunctioning
C)The card is for a token ring network
D)There is a port speed mismatch

Accepted Answer

Most likely there is a port speed mismatch between the switch and the card.
Key Takeaway: A NIC has to communicate at the same speed as the switch or else the communication will not take place. Most modern switches and cards can auto negotiate both the speed and duplex setting. For those devices that cannot auto negotiate, the speed and duplex must be made to match manually.

Question 16

You have a device that cannot browse the Internet, but can ping individual IP addresses on the Internet. The other workstations on the network seem to browse the Internet just fine. What is the most likely cause of this problem?
A)The DHCP server is down
B)The DNS server is down
C)The workstation has incorrect DNS settings
D)The router is blocking port 53 on both UDP and TCP

Accepted Answer

The workstation has the DNS settings configured improperly.
Key Takeaway: DNS lets us translate from human friendly names to the IP addresses computers use. We can tell it is a DNS problem because the traffic still goes out to the Internet by IP address. We know that the server is not down and that the router is not blocking port 53, because the other workstations can get out to the Internet. That leaves us with the fact that the DNS is configured improperly on the individual client.

Question 17

You notice a workstation on your network is continuously trying to broadcast packets over and over. What is the most likely cause?
A)Routing loop
B)Switching loop
C)Short in the Ethernet cable
D)Faulty NIC or NIC driver

Accepted Answer

A faulty NIC or NIC driver is the most likely cause of a network continuously trying to broadcast packets over and over.
Key Takeaway: A failing NIC will often send out a lot of packets that are just erroneous artifact. In modern networks, this will not affect the network much as the switch will probably prevent a broadcast storm, but a NIC wildly sending out a lot of erroneous packets is a hallmark of a failing NIC or corrupt driver.

Question 18

Melinda is a new network consultant and is supporting a network for a business. Melinda finds that the client uses subnetting due to a large number of hosts. All hosts have a subnet mask of 255.255.255.192. Melinda is trying to get a host with an IP address of 192.168.2.193 to communicate with a host at IP address of 192.168.2.246. Both hosts are already on the same switch. What additional device will Melinda need to route the traffic between these two hosts?
A)A network bridge
B)A circuit-level gateway
C)A network router
D)None. These addresses are on the same logical network.

Accepted Answer

No device is needed to route traffic as both of these devices are on the same network.
Key Takeaway: With the subnet mask of 255.255.255.192, every device with an address whose last octet is higher than 192 is on the same logical network. The system is including the first two bits of the last octet as a part of the network address. In this example every device with an IP address from 192.168.2.193 to 192.168.2.254 would be on the same network.

Question 19

You discover that a device on your network is creating a broadcast storm. You have switches that do not use VLANs or Spanning Tree Protocol. What is the most likely cause of the storm?
A)A routing loop
B)A switching loop
C)A faulty switch
D)A misconfigured router

Accepted Answer

A switching loop is the most common cause of a broadcast storm.
Key Takeaway: A switching loop occurs when there are two or more different pathways between any two devices. This is the most common cause of broadcast storms. Ways to fight these storms include segmenting your network with routers or VLANs, implementing the spanning tree protocol, and filtering broadcasts with layer 3 equipment such as routers or multilayer switches.

Question 20

Davis has noticed that one of the systems on his network has sporadic connection to the network. He is running a 100BaseT network, and the workstation is about 150 meters away from the switch. What is the most likely cause of the intermittent network issues?
A)A wireless router is conflicting with the wireless adaptor on the switch
B)The cable to the host is too long and the signal has attenuated
C)He needs to use coaxial cable for his 100baseT network
D)The bridge he had installed to propagate the signal has failed

Accepted Answer

The cable to the host is too long and the signal has attenuated. 100BaseT networks have a maximum length of 100 meters between devices.
Key Takeaway: The longest cable run you should have in a 100BaseT network is 100 Meters. Anything beyond this can lead to signal attenuation and intermittent network problems. You can fix this by shortening the run or putting a repeater, not a bridge, in place so that the run is now less than 100 meters.

Quiz 22: Management

You are trying to find out why a network card will not connect to the network. Which of the following should you check first?

A user calls in and reports that the Wi-Fi connection is disconnected when the house telephone rings. Which of the following could cause this issue?

Jack is a network administrator at his organization. Last night he accidentally messed up the connections running to the server. Today all users have been complaining about not having Internet connectivity and IP addresses in the 169.254.xxx.xxx series. What should Jack check first?

In a scenario where two computers have been assigned the same IP address, which of the following could be the result?

Which of the following parameters is not required if you want to communicate with a system on the same LAN?

John is working as a network administrator in his organization. A user is unable to connect to the network. All other users on that switch are able to connect successfully to the network. Which of the following could be a probable cause of this issue?

After connecting a PC to an available port on a switch, you find that the PC cannot access any of the resources on the LAN. No other PCs connected to the switch appear to be having any issues. What is the most likely cause of this problem?

If a connection that usually takes 9 hops to reach a particular web server is now taking 13 hops to reach it, how would it affect the connection?

Jack is planning to implement a fault tolerant mechanism on his company's web server. This is to avoid having to replace a failed drive and restore data without blocking data requests from many of the company's valuable customers. Which of these features should he implement on the web server?

Your 802.11n capable SOHO router is providing 11Mbps speeds to the network. What is most likely the issue?

Which command would you use on the Windows command line to ping a system continuously until you press ?

You have a device that cannot browse the Internet, but can ping individual IP addresses on the Internet. The other workstations on the network seem to browse the Internet just fine. What is the most likely cause of this problem?

You notice a workstation on your network is continuously trying to broadcast packets over and over. What is the most likely cause?

You discover that a device on your network is creating a broadcast storm. You have switches that do not use VLANs or Spanning Tree Protocol. What is the most likely cause of the storm?

Davis has noticed that one of the systems on his network has sporadic connection to the network. He is running a 100BaseT network, and the workstation is about 150 meters away from the switch. What is the most likely cause of the intermittent network issues?