Chapter 6 - Introduction to the Internet Protocol

Question 1

Protocols and ports  
SSH 22 DNS 53 SMTP 25 SFTP 22 
FTP 20, 21 TFTP 69 TELNET 23 
DHCP 67, 68 HTTP 80 HTTPS 443 SNMP 161 
RDP 3389 NTP 123 SIP 5060, 5061 SMB 445 
POP 110 IMAP 143 LDAP 389 LDAPS 636 
H.323 1720

Answer 1

Protocol types
ICMP UDP TCP IP

Remote file access
FTP/FTPS
SFTP
TFTP

Question 2

SMTP is used to send mail; POP3 is used to receive mail.

Answer 2

Post Office Protocol (TCP 110) Post Office Protocol (POP) gives us a storage facility for incoming mail, and the latest version is called POP3 (sound familiar?). Basically, how this protocol works is when a client device connects to a POP3 server, messages addressed to that client are released for downloading. A newer standard, IMAP, is being used more and more in place of POP3.

Question 3

Remote Desktop Protocol (TCP 3389) Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft. It allows you to connect to another computer and run programs.

Answer 3

Transport Layer Security/Secure Sockets Layer (TCP 995/465) Both Transport Layer Security (TLS) and its forerunner, Secure Sockets Layer (SSL), are cryptographic protocols that come in really handy for enabling secure online data-transfer activities like browsing the Web, instant messaging, Internet faxing, and so on.

Question 4

Transport Layer Security/Secure Sockets Layer (TCP 995/465)

them. They both use X.509 certificates and asymmetric cryptography to authenticate to the host they are communicating with and to exchange a key. This key is then used to encrypt data flowing between the hosts. This allows for data/message confidentiality, message integrity, and message authentication.

Answer 4

SIP (VoIP) (TCP or UDP 5060/TCP 5061) Session Initiation Protocol (SIP) is a hugely popular signaling protocol used to construct and deconstruct multimedia communication sessions for many things like voice and video calls, videoconferencing, streaming multimedia distribution, instant messaging, presence information, and online games over the Internet.

Question 5

RTP (VoIP) (UDP 5004/TCP 5005) Real-time Transport Protocol (RTP) describes a packet-formatting standard for delivering audio and video over the Internet.

Answer 5

MGCP (Multimedia) (TCP 2427/2727) Media Gateway Control Protocol (MGCP) is a standard protocol for handling the signaling and session management needed during a multimedia conference.

Question 6

MGCP can be used to set up, maintain, and terminate calls between multiple endpoints.

Answer 6

H.323 (Video) (TCP 1720) H.323 is a protocol that provides a standard for video on an IP network that defines how real-time audio, video, and data information is transmitted. This standard provides signaling, multimedia, and bandwidth control mechanisms. H.323 uses the RTP standard for communication.

Question 7

Simple Network Management Protocol (UDP 161) Simple Network Management Protocol (SNMP) collects and manipulates valuable network information. It gathers data by polling the devices on the network from a management station at fixed or random intervals, requiring them to disclose certain information.

Answer 7

Internet Group Management Protocol (IGMP) is the TCP/IP protocol used for managing IP multicast sessions.

Question 8

NetBIOS (TCP and UDP 137–139) Network Basic Input/Output System works only in the upper layers of the OSI model and allows for an interface on separate computers to communicate over a network.

Answer 8

Server Message Block (TCP 445) Server Message Block (SMB) is used for sharing access to files and printers and other communications between hosts on a Microsoft Windows network. SMB can run on UDP port 137 and 138 and on TCP port 137 and 139 using NetBIOS.

Question 9

Domain Name Service (TCP and UDP 53) Domain Name Service (DNS) resolves hostnames—specifically, Internet names, such as www.lammle.com—to their corresponding IP addresses.

Answer 9

Dynamic Host Configuration Protocol/Bootstrap Protocol (UDP 67/68) Dynamic Host Configuration Protocol (DHCP) assigns IP addresses to hosts with information provided by a server.

Question 10

The OSI model has seven layers and the DoD has four. At which layer does SMTP work in both models?

Answer 10

Application

Question 11

You need to have secure communications using HTTPS. What port number is used by default?

Answer 11

443

Question 12

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?

Answer 12

DHCP

Question 13

What protocol is used to find the hardware address of a local device?

Answer 13

ARP

Question 14

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 administer this server securely?

Answer 14

SSH

Question 15

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?

Answer 15

53

Question 16

Which of the following describe the DHCP Discover message? (Choose two.)

Answer 16

It uses FF:FF:FF:FF:FF:FF as a Layer 2 broadcast.

It uses UDP as the Transport layer protocol.

Question 17

What Layer 4 protocol is used for a Telnet connection, and what is the default port number?

Answer 17

TCP, 23

Question 18

Which statements are true regarding ICMP packets? (Choose two.)

Answer 18

They can provide hosts with information about network problems.

They are encapsulated within IP datagrams.

Question 19

Which of the following services use TCP? (Choose four.)

Answer 19

SMTP
SNMP
FTP
HTTP

Question 20

Which of the following services use UDP? (Choose three.)

Answer 20

DHCP

SNMP

TFTP