Net Essentials Study Set
When authenticating within Packet Tracer, which two items could you use?
an email address found in the NetAcad profile and a username associated with NetAcad Explanation: When Packet Tracer first opens, an authentication screen appears. Use the email address in the NetAcad profile or a username associated with NetAcad.
Which type of applications are best suited to use UDP as the transport layer protocol?
applications that require minimal transmission delay Explanation: UDP is a light-weight connectionless protocol that is well-suited for applications that are susceptible to delay or that do not need the features provided by TCP (guaranteed delivery, flow control, or sequencing).
What terms represent the maximum and actual speed that can be utilized by a device to transfer data?
bandwidth & throughput Explanation: Bandwidth measures the maximum rate at which a device can transfer data. However, in practice, the actual speed for data transfer could be reduced because of numerous factors like network congestion, overhead etc. This actual rate of transfer is known as throughput.
Which type of attack involves an attacker using a powerful computer to try a large number of possible passwords in rapid succession to gain access to a system?
brute force Explanation: In a brute force attack an attacker will try to gain access to a system by guessing passwords as fast as possible.
Which term is used to describe a network device that relies on another device to obtain information?
client Explanation: A client device has software installed which enables it to request the required service from a server device. For instance, a user who uses a web browser is effectively requesting pages from servers all over the web. In this case the browser is considered the client, whereas the device that is responsible for answering the request is considered the server.
Which type of network cable is used to connect the components that make up satellite communication systems?
coaxial Explanation: Coaxial cable is commonly used to connect the various components that make up satellite communication systems and cable TV.
Name the three private IP ranges
10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.31.255.255, 192.168.0.0 - 192.168.255.255
How many bits make up the single IPv6 hextet :10CD:?
16 Explanation: A hextet consists of 4 hexadecimal characters. Each hexadecimal character is represented by four bits, giving a total of 16 bits.
How many unique values are possible using a single binary digit?
2
What is the valid most compressed format possible of the IPv6 address 2001:0DB8:0000:AB00:0000:0000:0000:1234?
2001:DB8:0:AB00::1234 Explanation: There are two rules defining how an IPv6 address can be compressed. The first rule states that leading zeros in a hextet can be eliminated. The second rule states that a single :: can be used to represent one or more contiguous all zero hextets. There can be one and only one :: in an IPv6 address.
A DHCP server is used to assign IP addresses dynamically to the hosts on a network. The address pool is configured with 172.30.8.0/24. There are 7 printers on this network that need to use reserved static IP addresses from the pool. How many IP addresses in the pool are left to be assigned to other hosts?
247 Explanation: If the block of addresses allocated to the pool is 172.30.8.0/24, there are 254 IP addresses to be assigned to hosts on the network. As there are 7 printers which need to have their addresses assigned statically, then there are 247 IP addresses left for assignment.
What is the default subnet mask for an IP address of 198.133.219.4
255.255.255.0 Explanation: In classful IPv4 addressing, a network with the first octet of 198 is a Class C network with the default subnet mask of 255.255.255.0.
How is a DHCPDISCOVER transmitted on a network to reach a DHCP server?
A DHCPDISCOVER message is sent with the broadcast IP address as the destination address. Explanation: The DHCPDISCOVER message is sent by a DHCPv4 client and targets a broadcast IP along with the destination port 67. The DHCPv4 server or servers respond to the DHCPv4 clients by targeting port 68.
What are the three layers of a hierarchical network design model?
distribution, core, access Explanation: The Cisco hierarchical network design model divides the network into three distinct layers. The access layer provides connectivity for the users. The distribution layer is used to forward traffic from one local network to another. The core layer represents a high-speed backbone layer between networks. The network layer is part of the OSI model. The Internet layer is part of the TCP/IP model. The application layer is part of both the OSI and TCP/IP models.
Why should WEP not be used in wireless networks today?
easily crackable Explanation: Despite improvements, WEP is still vulnerable to various security issues including the ability to be cracked.
What type of server would use IMAP?
email Explanation: SMTP, IMAP, and POP are three application layer protocols for email applications.
A router is receiving a stream of incoming packets and does not contain a route to the remote destination network. What configuration can a network administrator issue in order to successfully forward the incoming packets
Add a default route Explanation: A router contains a routing table of all locally connected networks and the interfaces that connect to them. The routing tables can also contain the routes that the router uses to reach remote networks. Entries can be made to the routing table in two ways. The first is that the router via the use of a routing protocol can be dynamically updated by information received from other routers in the network. The second is that the entries can be manually entered by a network administrator. If the router cannot determine where to forward a packet, it will drop it. Network administrators can configure a default route to keep a packet from being dropped because the path to the destination network is not in the routing table. A default route is the interface through which the router forwards a packet containing an unknown destination IP network address.
A user is looking for a wireless headphone for listening to songs stored on a smartphone. What wireless technology would the headphone use?
Bluetooth Explanation: Bluetooth is a wireless technology for data exchange over a short distance. It is suitable for connecting devices with simple tasks, such as headsets, keyboards, mice, and printers. Wi-Fi is suitable for variety of applications with high speed wireless connectivity required or preferred. Infrared requires a direct line of sight between the transmitter and the receiver. 3G/4G are cellular network technologies to manage voice calls and data transmission between clients and service providers.
What process is used to place one message inside another message for transfer from the source to the destination?
encapsulation Explanation: Encapsulation is the process of placing one message format into another message format. An example is how a packet is placed in its entirety into the data field as it is encapsulated into a frame.
A host PC is attempting to lease an address through DHCP. What message is sent by the server to let the client know it is able to use the provided IP information?
DHCPACK Explanation: When a host uses DHCP to automatically configure an IP address, the typically sends two messages: the DHCPDISCOVER message and the DHCPREQUEST message. These two messages are usually sent as broadcasts to ensure that all DHCP servers receive them. The servers respond to these messages using DHCPOFFER, DHCPACK, and DHCPNACK messages, depending on the circumstance.
Which message does an IPv4 host use to reply when it receives a DHCPOFFER message from a DHCP server?
DHCPREQUEST Explanation: When the client receives the DHCPOFFER from the server, it sends back a DHCPREQUEST broadcast message. On receiving the DHCPREQUEST message, the server replies with a unicast DHCPACK message.
Which network device is used to translate a domain name to the associated IP address?
DNS server Explanation: A DNS server is a network device that is used to translate a domain name to its IP address. A user will identify a website using a domain name, such as www.cisco.com and a DNS server will translate it to an associated IP address.
What is a characteristic of a computer worm?
exploits vulnerabilities with the intent of propagating itself across a network Explanation: A worm is similar to a virus. However, a worm is self-spreading and can send copies of itself to connected hosts over the network.
The Institute of Electrical and Electronics Engineers is responsible for standards in which two areas?
Ethernet media access control and wireless LANs Explanation: Among the many standards for which the IEEE is responsible, the two major standards are IEEE 802.3 and IEEE 802.11. The IEEE 802.3 standard defines media access control (MAC) for wired Ethernet. The 802.11 standard defines a group of standards for implementing wireless local area networks (WLANs). The other options are standards that are developed and maintained by other standards organizations.
What are two advantages of using fiber-optic cabling to interconnect devices?
Fiber-optic cable is immune from EMI and RFI and they can extend several miles Explanation: Fiber-optic cables provide immunity to both EMI and RFI and a single cable can extend for several miles before regeneration is needed.
What will a Cisco LAN switch do if it receives an incoming frame and the destination MAC address is not listed in the MAC address table
Forward the frame out all ports except the port where the frame is received. Explanation: A LAN switch populates the MAC address table based on source MAC addresses. When a switch receives an incoming frame with a destination MAC address that is not listed in the MAC address table, the switch forwards the frame out all ports except for the ingress port of the frame. When the destination device responds, the switch adds the source MAC address and the port on which it was received to the MAC address table.
What specialized network device is responsible for permitting or blocking traffic between networks?
firewall Explanation: Firewalls are used to permit or block traffic between networks according to access control policies.
Which two parts are components of an IPv4 address?
Host portion and network portion Explanation: An IPv4 address is divided into two parts: a network portion - to identify the specific network on which a host resides, and a host portion - to identify specific hosts on a network. A subnet mask is used to identify the length of each portion.
What are two sources of electromagnetic interference that can affect data transmissions?
florescent light fixture & microwave oven Explanation: Electromagnetic interference or EMI is commonly caused by equipment such as microwave ovens and fluorescent light fixtures.
Which three steps must be completed to manually connect an Android or IOS device to a secured wireless network?
Input the authentication password, Enter the network SSID, Choose the correct security type Explanation: In order to connect an Android or IOS device to a Wi-Fi network manually, perform these steps:Enter the network SSID of the wireless network.Choose the security type used by the wireless network.Input the password to authenticate successfully.
Which statement accurately characterizes the evolution of threats to network security?
Internal threats can cause even greater damage than external threats. Explanation: Internal threats can be intentional or accidental and cause greater damage than external threats because the internal user has direct access to the internal corporate network and corporate data.
What is the purpose of a DMZ?
It allows external hosts to access specific company servers while maintaining the security restrictions for the internal network. Explanation: The DMZ is an area of the network that is accessible to both internal and external users. It is more secure than the external network but not as secure as the internal network. It allows external hosts to access internal servers.
What purpose does NAT64 serve in IPv6?
It converts IPv6 packets into IPv4 packets. Explanation: NAT64 is typically used in IPv6 when networks are being transitioned from IPv4 to IPv6. It allows the IPv6 networks to connect to IPv4 networks (such as the Internet), and works by translating the IPv6 packets into IPv4 packets.
What is a function of a DNS server?
It determines the IP address that is associated with a specific host domain name. Explanation: Hosts are assigned with IP addresses in order to communicate over the network. Hosts are registered with domain names so people can remember and recognize them easily. However, computers are connected through their IP addresses. DNS provides the service to map the domain name to its IP address.
A router receives an incoming packet and determines that the packet should be forwarded to a remote destination host. What will the router do to forward the packet
It encapsulates the frame with the destination MAC address by using the MAC address of the interface of the next-hop router. Explanation: A router contains a routing table of all locally connected networks and the interfaces that connect to them. The routing tables can also contain the routes that the router uses to reach remote networks. When a router determines that an incoming packet contains the destination host on a remote network, it encapsulates the frame to forward it towards to the next hop router. It uses the MAC address of the interface on the next hop router as the destination MAC address. The MAC address is obtained through ARP.
Why is DHCP for IPv4 preferred for use on large networks?
It is a more efficient way to manage IPv4 addresses than static address assignment is Explanation: Static IPv4 address assignment requires personnel to configure each network host with addresses manually. Large networks can change frequently and have many more hosts to configure than do small networks. DHCP provides a much more efficient means of configuring and managing IPv4 addresses on large networks than does static address assignment.
Which statement accurately describes dynamic NAT?
It provides an automated mapping of inside local to inside global IP addresses. Explanation: Dynamic NAT provides a dynamic mapping of inside local to inside global IP addresses. NAT is merely the one-to-one mapping of one address to another address without taking into account whether the address is public or private. DHCP is automatic assignment of IP addresses to hosts. DNS is mapping host names to IP addresses.
When a host sends a packet, how does it determine if the destination of the packet is on the same local network or on a remote network
It uses the subnet mask to compare the source and destination IP address. Explanation: When a host sends a packet, it uses the subnet mask to compare the source IPv4 address and the destination IPv4 address. If the network bits match, both the source and destination host are on the same local network. Otherwise, the destination host is on a remote network.
What is a disadvantage of deploying a peer-to-peer network model?
Lack of centralized administration. Explanation: The simplest peer-to-peer network consists of two computers that are directly connected to each other through the use of a wired or wireless connection. The primary disadvantages of a peer-to-peer network are its lack of central administration, minimal security, and its lack of scalability.
A wireless network was recently installed in a coffee shop and customer mobile devices are not receiving network configuration information. What should be done to correct the problem?
Make sure the DHCP server is functional. Explanation: End-user devices can request an address from a pool of addresses that are maintained by a DHCP server.
A consumer places a smartphone close to a pay terminal at a store and the shopping charge is successfully paid. Which type of wireless technology was used?
NFC Explanation: NFC is a wireless technology that allows data to be exchanged between devices that are in very close proximity to each other.
Which two protocols are used in the process of sending and receiving emails?
POP & SMTP Explanation: POP and SMTP are protocols used for email. POP is Post Office Protocol and is used by clients to retrieve email messages from a server. SMTP is Simple Mail Transfer Protocol and is used by clients to send email messages to a server.
Which two applications provide virtual terminal access to remote servers?
SSH & telenet Explanation: Telnet and SSH are two services that provide virtual terminal services to servers. DNS maps a domain name to its IP address. DHCP provides dynamic IP addressing information. SMTP provides email service.
A small publishing company has a network design such that when a broadcast is sent on the LAN, 200 devices receive the transmitted broadcast. How can the network administrator reduce the number of devices that receive broadcast traffic
Segment the LAN into smaller LANs and route between them. Explanation: By dividing the one big network into two smaller network, the network administrator has created two smaller broadcast domains. When a broadcast is sent on the network now, the broadcast will only be sent to the devices on the same Ethernet LAN. The other LAN will not receive the broadcast.
Which type of attack exploits human behavior to gain confidential information?
Social engineering
What action does the ARP process take when a host needs to build a frame, but the ARP cache does not contain an address mapping?
The ARP process sends out an ARP request to the Ethernet broadcast address to discover the MAC address of the destination device. Explanation: The address resolution protocol (ARP) maintains a cache of MAC to IPv4 address mappings on the local computer. If there is no mapping in the cache for a specific IPv4 address, then the ARP process sends an Ethernet broadcast on the local link in an attempt to resolve the destination IPv4 address to a MAC address.
What is the result if the default gateway address is misconfigured on a PC?
The PC can communicate with devices in the same network but not with those in remote networks. Explanation: The default gateway for a PC is the closest networking device that can forward traffic to other networks. If a PC has an incorrect or nonexistent default gateway address, it will not be able to communicate with devices in remote networks. However, communication would occur between devices in the same network with or without a default gateway.
A computer can access devices on the same network but cannot access devices on other networks. What is the probable cause of this problem
The computer has an invalid default gateway address. Explanation: The default gateway is the address of the device a host uses to access the Internet or another network. If the default gateway is missing or incorrect, that host will not be able to communicate outside the local network. Because the host can access other hosts on the local network, the network cable and the other parts of the IP configuration are working.
Which statement is true about MAC addresses?
The first three bytes are used by the vendor assigned OUI Explanation: A MAC address is composed of 6 bytes. The first 3 bytes are used for vendor identification and the last 3 bytes must be assigned a unique value within the same OUI. MAC addresses are implemented in hardware. A NIC needs a MAC address to communicate over the LAN. The IEEE regulates the MAC addresses.
What happens when a wireless access point is configured to stop broadcasting the SSID?
The network is invisible to those who are unaware of the SSID. Explanation: By default, wireless routers and access points broadcast SSIDs to all computers within the wireless range. This allows any wireless client to detect the network and to connect to it. The SSID broadcast feature can be turned off. When it is turned off, the network is no longer made public. It becomes invisible to clients that are not manually configured with the SSID.
Which statement describes the use of the ping command?
The ping command tests end-to-end connectivity between two devices. Explanation: The ping command is used to test end-to-end connectivity between the source and destination IP address. It measures the time it takes a test message to make a round trip between the two end points. However, if the message does not reach the destination, or in the case of delays, there is no way to determine where the problem is located.
How does a client computer determine what source port number to assign to a UDP header?
The port number is random within the range of dynamic port numbers. Explanation: The destination port number is normally a well-known or registered port number that is open on the destination device such as a server. The source port is randomly generated by the client computer from the 49152 to 65535 range.
Which three types of nodes should be assigned static IP addresses on a network?
gateways, servers, printers Explanation: Servers, printers, and intermediary devices, such as routers, switches, and access points should have statically assigned IP addresses so that they are accessible to users and available for remote management.
What is an advantage of UDP over TCP?
UDP communication requires less overhead. Explanation: TCP is a more reliable protocol and uses sequence numbers to realign packets that arrive out of order at the destination. Both UDP and TCP use port numbers to identify applications. UDP has less overhead than TCP because the UDP header has fewer bytes and UDP does not confirm the receipt of packets.
Which type of IPv6 address is not routable and used only for communication on a single subnet?
link-local address Explanation: Link-local addresses have relevance only on the local link. Routers will not forward packets that include a link-local address as either the source or destination address.
What what does the 100 in the 100BASE-T standard indicate?
megabits per second Explanation: 100BASE-T is an Ethernet standard that translates to 100 megabits per second, baseband transmission, and twisted pair cable.
What type of message is sent to a specific group of hosts?
multicast Explanation: A communication that has a single source going to a single destination is a unicast. A communication from a single source to a group of destinations is a multicast. A communication from a single source to all destinations on the same local network is a broadcast.
Which two functions are primary functions of a router?
path selection and packet forwarding Explanation: A router accepts a packet and accesses its routing table to determine the appropriate exit interface based on the destination address. The router then forwards the packet out of that interface.
Which type of network component can be used to share an attached printer to the network?
personal computer Explanation: A peripheral is a device that is not directly connected to a network. In order to be made available on a network, a host is responsible for sharing the peripheral across the network.
An administrator wants to configure a router so that users on the outside network can only establish HTTP connections to the internal web site. Which feature would the administrator configure to accomplish this?
port forwarding Explanation: Port forwarding allows connections to one port on the external interface to be redirected to a specific device and a specific port on the inside interface. In this way specific inside services can be accessible from the outside network without permitting all traffic to the inside device.
What is the purpose of protocols in data communications
providing the rules required for a specific type of communication to occur Explanation: Protocols provide rules that define how a message is transmitted across a network. Implementation requirements such as electronic and bandwidth details for data communication are specified by standards. Operating systems are not specified by protocols, but will implement protocols. Protocols determine how and when to send a message but they do not control the contents of a message.
Which type of network model describes the functions that must be completed at a particular layer, but does not specify exactly how each protocol should work
reference model Explanation: There are two common types of network communication models:Protocol model - This model closely matches the structure of a particular protocol suite and describes the functions that occur at each layer of protocols within the suite. The TCP/IP model is an example of a protocol model.Reference model - The primary purpose is to aid in a clearer understanding of the functions and processes necessary for network communications.This type of model does not specify exactly how a function should be accomplished. The OSI model is an example of a reference model.
Which three layers of the OSI model map to the application layer of the TCP/IP model?
session, application, presentation Explanation: The application layer of the TCP/IP model maps to the top three layers of the OSI model, which are the application, presentation, and session layers.
What is a socket?
the combination of a source IP address and port number or a destination IP address and port number Explanation: A socket is a combination of the source IP address and source port or the destination IP address and the destination port number.
Which logical address is used for delivery of data to a remote network
the destination IP address Explanation: The destination IP address is used for end-to-end delivery of data to a remote network. The destination MAC address is used for delivery on a local network. The destination port number identifies the application that should process the data at the destination. Source addresses identify the sender of the data.
Which criterion can be used to select the appropriate type of network media for a network?
the environment where the selected medium is to be installed Explanation: Criteria for choosing a network medium are the distance across which the selected medium can successfully carry a signal, the environment in which the selected medium is to be installed, the amount of data and the speed at which the data must be transmitted, and the cost of the medium and its installation.
If you were drawing a physical topology of your school network, what type of information would you include?
the location of devices in the building Explanation: A physical topology is a diagram that shows where all the devices are physically located in the building.
Which three pieces of information are identified by a URL?
the protocol that is being used, the location of the resource, the domain name that is being accessed Explanation: URLs are used to access specific content on a web server through a web browser. The URL identifies the protocol that is being used such as HTTP or FTP, the domain of the server, and the location of the resource on the server.
Which factor classifies a host as a server?
the software installed. Explanation: A server is a host with server software installed. Although CPU, memory, and the network connection will determine the performance of a server, it is the server software that provides desired server services.
What addressing information is recorded by a switch to build its MAC address table
the source Layer 2 address of incoming frames Explanation: A switch builds a MAC address table by inspecting incoming Layer 2 frames and recording the source MAC address found in the frame header. The discovered and recorded MAC address is then associated with the port used to receive the frame.
What is the purpose of using a source port number in a TCP communication?
to keep track of multiple conversations between devices Explanation: The source port number in a segment header is used to keep track of multiple conversations between devices. It is also used to keep an open entry for the response from the server. The incorrect options are more related to flow control and guaranteed delivery.
An employee is having connectivity issues. Why might a network technician try to ping the default gateway from the employee laptop?
to verify connectivity with the device that provides access to remote networks Explanation: The default gateway address is usually the address of the router interface. The router provides access to remote networks, so a successful ping to the default gateway would mean that the laptop is able to communicate with the router.
What layer of the TCP/IP suite makes sure that all the data packets of a message arrive safely at the destination?
transport Explanation: The transport layer is responsible for managing the delivery of packets. TCP monitors the packets and if a packet is missing, it will request that it be sent again.
Which two OSI model layers have the same functionality as two layers of the TCP/IP model?
transport and network Explanation: The OSI transport layer is functionally equivalent to the TCP/IP transport layer, and the OSI network layer is equivalent to the TCP/IP internet layer. The OSI data link and physical layers together are equivalent to the TCP/IP network access layer. The OSI session layer (with the presentation layer) is included within the TCP/IP application layer.
Which type of network cable is commonly used to connect office computers to the local network?
twisted-pair cable Explanation: Twisted-pair is a type of copper cable used to interconnect devices on a local network.
Which three attacks exploit human behavior?
vishing, pretexting, phishing Explanation: Attacks aimed at exploiting human behavior such as pretexting, phishing, and vishing are commonly used by hackers to obtain information directly from authorized users.
