Unit 5-10 Exam II Flashcards
- Which statement describes a feature of the IP protocol?
IP relies on Layer 2 protocols for transmission error control.
MAC addresses are used during the IP packet encapsulation.
IP relies on upper layer services to handle situations of missing or out-of-order packets.
IP encapsulation is modified based on network media.
IP relies on upper layer services to handle situations of missing or out-of-order packets.
Explanation: IP protocol is a connection-less protocol, considered unreliable in terms of end-to-end delivery. It does not provide error control in the cases where receiving packets are out-of-order or in cases of missing packets. It relies on upper layer services, such as TCP, to resolve these issues.
What is message encoding?
message encoding : the process of converting information from one format into another acceptable for transmission
What is message sizing?
message sizing : the process of breaking up a long message into individual pieces before being sent over the network
- Which method would an IPv6-enabled host using SLAAC employ to learn the address of the default gateway?
router advertisement messages received from the link router
router solicitation messages received from the link router
neighbor advertisement messages received from link neighbors
neighbor solicitation messages sent to link neighbors
router advertisement messages received from the link router
42. A user issues a ping 192.168.250.103 command and receives a response that includes a code of 1. What does this code represent? network unreachable port unreachable protocol unreachable host unreachable
host unreachable
- What are three responsibilities of the transport layer? (Choose three.)
identifying the applications and services on the client and server that should handle transmitted data
conducting error detection of the contents in frames
meeting the reliability requirements of applications, if any
directing packets towards the destination network
formatting data into a compatible form for receipt by the destination devices
multiplexing multiple communication streams from many users or applications on the same network
identifying the applications and services on the client and server that should handle transmitted data
meeting the reliability requirements of applications, if any
multiplexing multiple communication streams from many users or applications on the same network
Explanation: The transport layer has several responsibilities. Some of the primary responsibilities include the following:
Tracking the individual communication streams between applications on the source and destination hosts
Segmenting data at the source and reassembling the data at the destination
Identifying the proper application for each communication stream through the use of port numbers
Multiplexing the communications of multiple users or applications over a single network
Managing the reliability requirements of applications
- How does network scanning help assess operations security?
It can detect open TCP ports on network systems.
It can detect weak or blank passwords.
It can simulate attacks from malicious sources.
It can log abnormal activity.
It can detect open TCP ports on network systems.
Explanation: Network scanning can help a network administrator strengthen the security of the network and systems by identifying open TCP and UDP ports that could be targets of an attack.
- Which two operations are provided by TCP but not by UDP? (Choose two.)
retransmitting any unacknowledged data
acknowledging received data
reconstructing data in the order received
identifying the applications
tracking individual conversations
retransmitting any unacknowledged data
acknowledging received data
Explanation: Numbering and tracking data segments, acknowledging received data, and retransmitting any unacknowledged data are reliability operations to ensure that all of the data arrives at the destination. UDP does not provide reliability. Both TCP and UDP identify the applications and track individual conversations. UDP does not number data segments and reconstructs data in the order that it is received.
- A user is executing a tracert to a remote device. At what point would a router, which is in the path to the destination device, stop forwarding the packet?
when the router receives an ICMP Time Exceeded message
when the RTT value reaches zero
when the values of both the Echo Request and Echo Reply messages reach zero
when the host responds with an ICMP Echo Reply message
when the value in the TTL field reaches zero
Explanation: When a router receives a traceroute packet, the value in the TTL field is decremented by 1. When the value in the field reaches zero, the receiving router will not forward the packet, and will send an ICMP Time Exceeded message back to the source.
- A network administrator is testing network connectivity by issuing the ping command on a router. Which symbol will be displayed to indicate that a time expired during the wait for an ICMP echo reply message?
U
.
!
$
.
Explanation: When the ping command is issued on a router, the most common indicators are as follows:
! – indicates receipt of an ICMP echo reply message
. – indicates a time expired while waiting for an ICMP echo reply message
U – an ICMP message of unreachability was received
- A technician is configuring email on a mobile device. The user wants to be able to keep the original email on the server, organize it into folders, and synchronize the folders between the mobile device and the server. Which email protocol should the technician use?
SMTP
MIME
POP3
IMAP
IMAP
- At which OSI layer is a source MAC address added to a PDU during the encapsulation process?
application layer
presentation layer
data link layer
transport layer
data link layer
- Which value, that is contained in an IPv4 header field, is decremented by each router that receives a packet?
Time-to-Live
Fragment Offset
Header Length
Differentiated Services
Time-to-Live
Explanation: When a router receives a packet, the router will decrement the Time-to-Live (TTL) field by one. When the field reaches zero, the receiving router will discard the packet and will send an ICMP Time Exceeded message to the sender.
- Which two ICMP messages are used by both IPv4 and IPv6 protocols? (Choose two.)
route redirection neighbor solicitation router solicitation router advertisement protocol unreachable
route redirection
protocol unreachable
Explanation: The ICMP messages common to both ICMPv4 and ICMPv6 include: host confirmation, destination (net, host, protocol, port) or service unreachable, time exceeded, and route redirection. Router solicitation, neighbor solicitation, and router advertisement are new protocols implemented in ICMPv6.
- What mechanism is used by a router to prevent a received IPv4 packet from traveling endlessly on a network?
It checks the value of the TTL field and if it is 100, it discards the packet and sends a Destination Unreachable message to the source host.
It decrements the value of the TTL field by 1 and if the result is 0, it discards the packet and sends a Time Exceeded message to the source host.
It checks the value of the TTL field and if it is 0, it discards the packet and sends a Destination Unreachable message to the source host.
It increments the value of the TTL field by 1 and if the result is 100, it discards the packet and sends a Parameter Problem message to the source host.
It decrements the value of the TTL field by 1 and if the result is 0, it discards the packet and sends a Time Exceeded message to the source host.
What are three ICMP messages used only via ICMPv6
Router solicitation, neighbor solicitation, and router advertisement are new protocols implemented in ICMPv6.
- A device has been assigned the IPv6 address of 2001:0db8:cafe:4500:1000:00d8:0058:00ab/64. Which is the host identifier of the device?
2001:0db8:cafe:4500:1000:00d8:0058:00ab
00ab
2001:0db8:cafe:4500
1000:00d8:0058:00ab
1000:00d8:0058:00ab
Explanation: The address has a prefix length of /64. Thus the first 64 bits represent the network portion, whereas the last 64 bits represent the host portion of the IPv6 address.
- What three application layer protocols are part of the TCP/IP protocol suite? (Choose three.)
DHCP PPP FTP DNS NAT ARP
FTP
DNS
DHCP
Explanation: DNS, DHCP, and FTP are all application layer protocols in the TCP/IP protocol suite. ARP and PPP are network access layer protocols, and NAT is an internet layer protocol in the TCP/IP protocol suite.
- 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 IP address.
The cable is not connected properly to the NIC.
The computer has an incorrect subnet mask.
The computer has an invalid default gateway address.
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.
- A user who is unable to connect to the file server contacts the help desk. The helpdesk technician asks the user to ping the IP address of the default gateway that is configured on the workstation. What is the purpose for this ping command?
to resolve the domain name of the file server to its IP address
to request that gateway forward the connection request to the file server
to obtain a dynamic IP address from the server
to test that the host has the capability to reach hosts on other networks
to test that the host has the capability to reach hosts on other networks
Explanation: The ping command is used to test connectivity between hosts. The other options describe tasks not performed by ping . Pinging the default gateway will test whether the host has the capability to reach hosts on its own network and on other networks.
- A user gets an IP address of 192.168.0.1 from the company network administrator. A friend of the user at a different company gets the same IP address on another PC. How can two PCs use the same IP address and still reach the Internet, send and receive email, and search the web?
ISPs use Domain Name Service to change a user IP address into a public IP address that can be used on the Internet.
Both users must be using the same Internet Service Provider.
Both users must be on the same network.
ISPs use Network Address Translation to change a user IP address into an address that can be used on the Internet.
ISPs use Network Address Translation to change a user IP address into an address that can be used on the Internet.
Explanation: As user traffic from behind an ISP firewall reaches the gateway device, Network Address Translation changes private IP addresses into a public, routable IP address. Private user addresses remain hidden from the public Internet, and thus more than one user can have the same private IP address, regardless of ISP.
- How many host addresses are available on the 192.168.10.128/26 network?
30 32 60 62 64
62
- What are the three ranges of IP addresses that are reserved for internal private use? (Choose three.)
- 100.0.0/14
- 168.0.0/16
- 31.7.0/24
- 16.0.0/12
- 0.0.0/8
- 16.0.0/12
- 16.0.0/12
- 0.0.0/8
- 168.0.0/16
- 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?
DHCPDISCOVER DHCPOFFER DHCPREQUEST DHCPACK DHCPNACK
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.
- An employee complains that a Windows PC cannot connect to the Internet. A network technician issues the ipconfig command on the PC and is shown an IP address of 169.254.10.3. Which two conclusions can be drawn? (Choose two.)
The PC is configured to obtain an IP address automatically.
The default gateway address is not configured.
The DNS server address is misconfigured.
The enterprise network is misconfigured for dynamic routing.
The PC cannot contact a DHCP server.
The PC is configured to obtain an IP address automatically.
The PC cannot contact a DHCP server.
- What is a function of the tracert command that differs from the ping command when they are used on a workstation?
The tracert command is used to test the connectivity between two devices.
The tracert command reaches the destination faster.
The tracert command shows the information of routers in the path.
The tracert command sends one ICMP message to each hop in the path.
The tracert command shows the information of routers in the path.
Explanation: The tracert command sends three pings to each hop (router) in the path toward the destination and displays the domain name and IP address of hops from their responses. Because tracert uses the ping command, the travel time is the same as a standalone ping command. The primary function of a standalone ping command is to test the connectivity between two hosts.
- Which two functions or operations are performed by the MAC sublayer? (Choose two.)
It is responsible for Media Access Control.
It performs the function of NIC driver software.
It adds a header and trailer to form an OSI Layer 2 PDU.
It handles communication between upper and lower layers.
It adds control information to network protocol layer data.
It is responsible for Media Access Control.
It adds a header and trailer to form an OSI Layer 2 PDU.
Explanation: The MAC sublayer is the lower of the two data link sublayers and is closest to the physical layer. The two primary functions of the MAC sublayer are to encapsulate the data from the upper layer protocols and to control access to the media.
- Which field in an IPv4 packet header will typically stay the same during its transmission?
Flag
Time-to-Live
Packet Length
Destination Address
Destination Address
Explanation: The value in the Destination Address field in an IPv4 header will stay the same during its transmission. The other options might change during its transmission.
