Ch. 6

Question 1

1. The OSI model has seven layers and the DoD has four. At which layer does SMTP work in both models?
A. Network
B. Transport
C. Session
D. Application
E. Internet

Answer 1

1. D. SMTP resides at the Application layer of the OSI and DoD models.

Question 2

2. You need to have secure communications using HTTPS. What port number is used by default?
A. 69
B. 23
C. 21
D. 443

Answer 2

2. D. HTTPS, or Secure HTTP, uses port 443 by default.

Question 3

3. You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this?
A. SMTP
B. SNMP
C. DHCP
D. ARP

Answer 3

3. C. Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your network. DHCP can provide a lot of information, but the most common is IP address, subnet mask, default gateway, and DNS information.

Question 4

4. What protocol is used to find the hardware address of a local device?
A. RARP
B. ARP
C. IP
D. ICMP
E. BootP

Answer 4

4. B. Address Resolution Protocol (ARP) is used to find the hardware address from a known IP address.

Question 5

5. You need to log in to a Unix server across a network that is not secure. Which of the following protocols will allow you to remotely administrator this server securely?
A. Telnet
B. SSH
C. SFTP
D. HTTP

Answer 5

5. B. Secure Shell (SSH) allows you to remotely administer router, switches, and even servers securely.

Question 6

6. If you can ping by IP address but not by hostname, or FQDN, which of the following port numbers is related to the server process that is involved?
A. 21
B. 23
C. 53
D. 69
E. 80

Answer 6

6. C. The problem is with DNS, which uses both TCP and UDP port 53.

Question 7

7. Which of the following describe the DHCP Discover message? (Choose two.)
   A. It uses FF:FF:FF:FF:FF:FF as a Layer 2 broadcast.
   B. It uses UDP as the Transport layer protocol.
   C. It uses TCP as the Transport layer protocol.
   D. It does not use a Layer 2 destination address.

Answer 7

7. A, B. A client that sends out a DHCP Discover message in order to receive an IP address sends out a broadcast at both Layer 2 and Layer 3. The Layer 2 broadcast is all Fs in hex, or FF:FF:FF:FF:FF:FF. The Layer 3 broadcast is 255.255.255.255, which means all networks and all hosts. DHCP is connectionless, which means it uses User Datagram Protocol (UDP) at the Transport layer, also called the Host-to-Host layer.

Question 8

8. What Layer 4 protocol is used for a Telnet connection, and what is the default port number?
A. IP, 6
B. TCP, 21
C. UDP, 23
D. ICMP, 21
E. TCP, 23

Answer 8

8. E. Telnet uses TCP at the Transport layer with a default port number of 23.

Question 9

9. Which statements are true regarding ICMP packets? (Choose two.)
   A. They acknowledge receipt of a TCP segment.
   B. They guarantee datagram delivery.
   C. They can provide hosts with information about network problems.
   D. They are encapsulated within IP datagrams.
   E. They are encapsulated within UDP datagrams.

Answer 9

9. C, D. Internet Control Message Protocol (ICMP) is used to send error messages through the network, but ICMP does not work alone. Every segment or ICMP payload must be encapsulated within an IP datagram (or packet).

Question 10

10. Which of the following services use TCP? (Choose three.)
A. DHCP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. TFTP

Answer 10

10. B, D, E. SMTP, FTP, and HTTP use TCP.

Question 11

11. Which of the following services use UDP? (Choose three.)
A. DHCP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. TFTP

Answer 11

11. A, C, F. DHCP, SNMP, and TFTP use UDP. SMTP, FTP, and HTTP use TCP.

Question 12

12. Which of the following TCP/IP protocols are used at the Application layer of the OSI model? (Choose three.)
A. IP
B. TCP
C. Telnet
D. FTP
E. TFTP

Answer 12

12. C, D, E. Telnet, File Transfer Protocol (FTP), and Trivial FTP (TFTP) are all Application layer protocols. IP is a Network layer protocol. Transmission Control Protocol (TCP) is a Transport layer protocol.

Question 13

13. Which of the following protocols is used by email servers to exchange messages with one another? Choose all that appply.
A. POP3
B. IMAP
C. SMTP
D. HTTP

Answer 13

13. C. SMTP is used by a client to send mail to its server and by that server to send mail to another server. POP3 and IMAP are used by clients to retrieve their mail from the server that stores it until it is retrieved. HTTP is only used with web-based mail services.

Question 14

14. You need to have a connection to run applications that are installed on only your desktop computer at your office. Which protocol will provide a GUI interface to your work computer?
A. Telnet
B. FTP
C. RDP
D. IMAP
E. SMTP

Answer 14

14. C. Remote Desktop Protocol (RDP) allows you to connect to a remote computer and run programs, as Telnet does. However, the large advantage that RDP has over Telnet is that RDP allows you to have a GUI interface connection.

Question 15

15. Which of the following protocols can use TCP and UDP, permits authentication and secure polling of network devices, and allows for automated alerts and reports on network devices? Choose all that appply.
A. DNS
B. SNMP
C. SMTP
D. TCP

Answer 15

15. B. Simple Network Management Protocol is typically implemented using version 3, which allows for a connection-oriented service, authentication and secure polling of network devices, and alerts and reports on network devices.

Question 16

16. You need to transfer files between two hosts. Which two protocols can you use?
A. SNMP
B. SCP
C. RIP
D. NTP
E. FTP

Answer 16

16. B, E. Secure Copy Protocol (SCP) and File Transfer Protocol (FTP) can be used to transfer files between two systems.

Question 17

17. What layer in the IP stack is equivalent to the Transport layer of the OSI model?
A. Application
B. Host-to-Host
C. Internet
D. Network Access

Answer 17

17. B. The four layers of the IP stack (also called the DoD model) are Application/Process, Host-to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport layer of the OSI model.

Question 18

18. You need to make sure that the time is consistent across all your network devices. What protocol do you need to run on your network?
A. FTP
B. SCP
C. NTP
E. RTP

Answer 18

18. C. Network Time Protocol will ensure a consistent time across network devices on the network.

Question 19

19. Which of the following allows a server to distinguish among different simultaneous requests from the same host? Choose all that appply.
    A. They have different port numbers.
    B. A NAT server changes the IP address for subsequent requests.
    C. A server is unable to accept multiple simultaneous sessions from the same host. One session must end before another can begin.
    D. The MAC address for each one is unique.

Answer 19

19. A. Through the use of port numbers, TCP and UDP can establish multiple sessions between the same two hosts without creating any confusion. The sessions can be between the same or different applications, such as multiple web-browsing sessions or a web-browsing session and an FTP session.

Question 20

20. Which of the following uses both TCP and UDP? Choose all that appply.
A. FTP
B. SMTP
C. Telnet
D. DNS

Answer 20

20. D. DNS uses TCP for zone exchanges between servers and UDP when a client is trying to resolve a hostname to an IP address.