Item: 1 (Ref:Cert-N10-005.2.3.5)

You are configuring DHCP options on your organization's DHCP server. You need to configure the list of DNS servers for all DHCP clients. Which DHCP option code should you configure for the server?

1

3

6

15

1. (Ref:Cert-N10-005.2.3.5)

Answer: 6

Explanation: You should use DHCP option code 6. This option is for configuring the DNS servers and is usually configured at the server level.

DHCP option code 1 is for configuring the subnet mask and is usually configured at the scope level.

DHCP option code 3 is for configuring the router or default gateway and is usually configured at the scope level.

DHCP option code 15 is for configuring the domain name that the DHCP clients will use, and is usually configured at the server level.

Item: 2 (Ref:Cert-N10-005.3.1.3)

You have several devices that need to be directly connected. You need to determine how many crossover cables you need. The connections are as follows:

Connection 1 - two computers with legacy network interface cards (NICs)

Connection 2 - two legacy hubs

Connection 3 - a legacy switch and an MDIX-compliant switch

Connection 4 - two MDIX-compliant switches

How many crossover cables do you need?

1

2

3

4

2. (Ref:Cert-N10-005.3.1.3)

Answer: 3

Explanation: You will need three crossover cables for the given connections. Crossover cables physically perform the crossover function when connecting two devices. A crossover cable should be used when connecting legacy NICs, hubs, and switches.

An MDIX-compliant switch will perform the crossover function internally. A crossover cable is not required when two MDIX-compliant devices are attached, but both devices must be MDIX-compliant.

In a crossover cable, each end of the crossover cable is configured differently. The wiring scheme for a crossover cable is shown below:

Pin 1 (End 1) - Orange/White      Pin 1 (End 2) - Green/White

Pin 2 (End 1) - Orange           Pin 2 (End 2) - Green

Pin 3 (End 1) - Green/White      Pin 3 (End 2) - Orange/White

Pin 4 (End 1) - Blue           Pin 4 (End 2) - Blue

Pin 5 (End 1) - Blue/White      Pin 5 (End 2) - Blue/White

Pin 6 (End 1) - Green           Pin 6 (End 2) - Orange

Pin 7 (End 1) - Brown/White      Pin 7 (End 2) - Brown/White

Pin 8 (End 1) - Brown           Pin 8 (End 2) - Brown

Item: 3 (Ref:Cert-N10-005.1.1.7)

Which OSI layer is responsible for the reliable delivery of segments without error?

Network

Transport

Data Link

Application

3. (Ref:Cert-N10-005.1.1.7)

Answer: Transport

Explanation: The Transport layer is responsible for the reliable delivery of segments without error. This means that the Transport layer is not only responsible for making sure that segments of data are delivered, but also for ensuring that segments of data arrive without error. The Transport layer uses segment sequencing to put any incorrectly ordered segments into the correct sequence.

The layers of the OSI model, along with their layer numbers, are shown below:

Layer 1 - Physical layer

Layer 2 - Data Link layer

Layer 3 - Network layer

Layer 4 - Transport layer

Layer 5 - Session layer

Layer 6 - Presentation layer

Layer 7 - Application layer

Item: 4 (Ref:Cert-N10-005.1.5.4)

Which well-known port is used to forward e-mail on the Internet between e-mail servers?

23

25

110

161

4. (Ref:Cert-N10-005.1.5.4)

Answer: 25

Explanation: Ports allow more than one service or application to communicate at the same time between computers. Simple Mail Transfer Protocol (SMTP) uses port 25 to communicate e-mail transfers. Administrators can assign additional ports for communication on an intranet and through the Internet. There are a total of 65,536 ports each for TCP and UDP. Of these, only 1,024 ports are considered well known and, therefore, reserved for a particular service.

Port 23 is used by Telnet for remote administration.

Port 110 is used by Post Office Protocol Version 3 (POP3) for e-mail.

Port 161 is used by Simple Network Management Protocol (SNMP) for network diagnostics.

Item: 5 (Ref:Cert-N10-005.1.2.6)

Which functions does a network interface card perform? (Choose three.)

buffering data to and from the network medium

acting as the operating system for the network

reventing the NetBIOS from generating signals

making a physical connection to the network medium

converting serial data to parallel and parallel data to serial

shutting down disconnected or damaged terminals automatically

5. (Ref:Cert-N10-005.1.2.6)

Answer: buffering data to and from the network medium; making a physical connection to the network medium; converting serial data to parallel and parallel data to serial

Explanation: The network interface card (NIC) buffers data, changes parallel data into serial data and vice versa, follows specific rules controlling access to the network cable, and provides a physical connection to the network.

Because a NIC provides the primary connection from the computer to the network media, it must be compatible with both. A NIC can connect to the network with an RJ-45, a BNC, or an AUI connector. The NIC converts parallel data from the computer's internal bus and converts it to serial data that must go out on the network cable. It also converts incoming serial data to parallel data.

The NIC cannot shut down disconnected or damaged terminals, has no particular relationship to NetBIOS, and does not act as the operating system for the network.

Item: 6 (Ref:Cert-N10-005.1.5.7)

A network technician contacts you regarding what he believes is suspicious behavior on the network. He has noticed communication over TCP port 123 between his computer and a server on the Internet. Which protocol is causing this communication?

FTP

SSH

SMTP

NTP

6. (Ref:Cert-N10-005.1.5.7)

Answer: NTP

Explanation: Network Time Protocol (NTP) communicates over TCP port 123. It is responsible for synchronizing the clock settings on a computer. Proper clock synchronization is vital for many directory service applications. Communication over TCP port 123 is not a reason to be alarmed. NTP works at the Application layers of the OSI model.

File Transfer Protocol (FTP) communicates over TCP ports 20 and 21 to transfer files. Secure Shell (SSH) communicates over TCP port 22 to allow secure data transfer. Simple Mail Transfer Protocol (SMTP) communicates over TCP port 25 to transfer e-mail messages.

Item: 7 (Ref:Cert-N10-005.2.1.26)

Your network contains several virtual LANs (VLANs). What is a benefit of using this technology?

It allows users on a LAN to communicate with remote networks.

It connects small networks together to form a single large network.

It allows networks to be segmented logically without being physically rewired.

It allows users from different segments to communicate with each other.

7. (Ref:Cert-N10-005.2.1.26)

Answer: It allows networks to be segmented logically without being physically rewired

Explanation: A virtual LAN (VLAN) is a networking technology that allows networks to be segmented logically without having to be physically rewired.

In a traditional Ethernet network, you can replace all hubs with VLAN switches. This creates virtual network segments whose logical topology is independent of the physical topology of the wiring. Each station is assigned a VLAN identification number (ID), and stations with the same VLAN ID function as though they are all on the same physical network segment, no matter which physical switch they are connected to. Only devices with the same VLAN ID will receive broadcasts sent by a host. The assignment of VLAN IDs is done at the port level on the switches themselves. Moving a host to another department only requires the assignment of a different VLAN ID to the port on the switch to which the host is connected. No rewiring of cables is necessary.

The primary benefit of having a VLAN is that users can be grouped together according to their need for network communication, regardless of their actual physical locations. Membership in a VLAN segment, called a VLAN group, is controlled by the network management software, which allows users to be grouped according to their needs.

Item: 8 (Ref:Cert-N10-005.1.1.4)

What are the key functions of the OSI Network layer? (Choose two.)

flow control

path selection

data segmentation

logical addressing

physical addressing

8. (Ref:Cert-N10-005.1.1.4)

Answer: Path Selection, Logical addressing

Explanation: The key functions of the OSI Network layer are logical addressing and path selection. Packets/datagrams are exchanged between the Network layers of two systems. TCP/IP packets contain an IP header and the data. The Network layer includes the following functions:

Routing

Controlling subnet traffic

Fragmenting frames

Mapping logical addresses to physical addresses

Accounting for subnet usage

Network, or logical, addresses contain a network portion and a host portion. Network addresses are stored in the routing table of the router and are used to quickly determine the interface from which to route a packet to reach its destination. Once the packets arrive at the destination network address, the local router can determine where to forward the packets, based on the host address of the destination host.

Flow control, error notification, physical device addressing, and specification of the networking topology take place at the Data Link layer. Note that error notification takes place at the Data Link layer, while error correction is a function of the Transport layer. In addition, the Transport layer specifies whether the delivery method is reliable or unreliable (best-effort delivery), and handles the segmentation and reassembly of data into a data stream.

Physical addressing of a device occurs at the Data Link layer. The Data Link layer uses the address to determine if it is necessary to pass the message up the protocol stack and which upper-layer stack to pass it to. The Data Link layer supports both connection-oriented and connectionless services and provides for frame sequencing and flow control.

Item: 9 (Ref:Cert-N10-005.4.3.19)

Host A wants to communicate with Host B as shown in the following network exhibit:

[image]
Which three statements are true? (Choose three. Each answer is part of the solution.)

Host A will send an ARP request for the router's MAC address.

Host A will send an ARP request for Host B's MAC address.

Host A will send a frame with the destination MAC address of the router.

Host A will send a frame with the destination MAC address of Host B.

The switch will forward the frame to Host B.

The switch will forward the frame to the router.

9. (Ref:Cert-N10-005.4.3.19)

Answer: Host A will send an ARP request for Host B's MAC address.; Host A will send a frame with the destination MAC address of Host B.; The switch will forward the frame to Host B.

Explanation: Host A will send out an ARP request for the MAC address of Host B. Host A will then send a data frame to the switch with a destination MAC address of Host B. Finally, the switch will forward the frame to Host B.

Host A and Host B are connected to the same subnet, 192.168.1.32 /27, and are thus within the same VLAN. For this reason, traffic between the two hosts does not need to be sent to their default gateway to be routed. Hosts are able to ARP and build unicast frames for hosts on the same subnet. The switch will receive the frame and forward it to the appropriate host based on a MAC address table lookup. The router is not involved in this scenario.

Host A will not send an ARP request for the router's MAC address because routing is not required between hosts on the same subnet.

Host A will not send a frame with the destination MAC address of the router because routing is not required between hosts on the same subnet.

The switch will not forward the frame to the router because routing is not required between hosts on the same subnet.

Item: 10 (Ref:Cert-N10-005.1.3.14)

To which network class does the IP address 196.22.14.42 belong?

Class A

Class B

Class C

Class D

Class E

10. (Ref:Cert-N10-005.1.3.14)

Answer: Class C

Explanation: Class C addresses range from 192 to 223 decimal, or 11000000 to 11011111 binary. The first three bits in a Class C address are always 110. Class C addresses use the first three octets for the network address and the last octet for the host address. With one octet to use for the hosts, you can assign the addresses 1 through 255 (decimal) for the host ID, which is 00000001 through 11111111 in binary.

The address class ranges are listed below in binary and decimal:

Class A: 00000000 - 1111110 / 0 - 126

Class B: 10000000 - 10111111 / 128 - 191

Class C: 11000000 - 11011111 / 192 - 223

Class D: 11100000 - 11101111 / 224 - 239

Class E: 11110000 - 11111111 / 240 - 255

Note that the 127 network address is used for loopback.

Also notice that the most significant bit, the left-most bit, is a zero for all Class A addresses. For Class B addresses, the zero shifts to the right one place, which means that the two most significant bits in all Class B addresses are 10. The zero shifts again for Class C, which means that the three most significant bits in all Class C addresses are 110. This "shifting" continues for Class D and Class E. Knowing this pattern enables you to determine the class of a binary IP address simply by looking at the most significant bits.