Chapter 3 Concepts

Question 1

Transmission Control Protocol

Answer 1

Transmission control protocol provides connection-oriented traffic (or guaranteed delivery). TCP uses a 3-way handshake to guarantee delivery. Client sends a SYN packet, server responds with a SYN/ACK packet, client responds with ACK packet to finish handshake.

Question 2

User Datagram Protocol

Answer 2

User datagram protocol provides connectionless (or best effort) traffic. The ping command and audio/video streaming use UDP.

Question 3

Internet Protocol

Answer 3

The internet protocol identifies hosts in a TCP/IP network and delivers traffic from one host to another using IP addresses. IPv4 uses 32 bit address and IPv6 uses 128 bit address

Question 4

Internet Control Message Protocol

Answer 4

Internet control message protocol is used for testing basic connectivity and includes tools such as ping, pathping, and tracert.

Question 5

Address Resolution Protocol

Answer 5

Address resolution protocol resolves IPv4 addresses to media access control (MAC) address. TCP/IP uses the IP address to get the packet to the correct network, but once it arrives on the network, it uses the MAC or ARP to get the packet to the correct host.

Question 6

Real-Time Transport Protocol (RTP)

Answer 6

Real-time transport protocol is used to deliver audio and video over IP networks.

Question 7

Secure Real-Time Transport Protocol (SRTP)

Answer 7

Secure real-time transport protocol provides encryption, message authentication, and integrity for real-time transport protocol.

Question 8

File Transfer Protocol (FTP)

Answer 8

File transfer protocol uploads and downloads large files to and from an FTP server. FTP transmits data in cleartext. FTP active mode uses TCP port 21 for control signals and TCP port 20 for data. FTP passive mode uses TCP port 21 for signals but a random TCP port for data.

Question 9

Trivial File Transfer Protocol (TFTP)

Answer 9

Trivial file transfer protocol use UDP port 69 and is used to transfer smaller amounts of data such as when communicating with network devices.

Question 10

Secure Shell (SSH)

Answer 10

Secure shell (SSH) encrypts traffic in transit and can be used to encrypt other protocols such as FTP. When SSH encrypts traffic it uses TCP port 22.

Question 11

Secure Sockets Layer (SSL)

Answer 11

Secure sockets layer (SSL) protocol was the primary method to secure HTTP traffic. It has been compromised and is not recommended for use.

Question 12

Transport Layer Security (TLS)

Answer 12

Transport layer security (TLS) is the designated replacement for SSL.

Question 13

IPsec

Answer 13

Internet protocol security (IPsec) is used to encrypt IP traffic. It is native to IPv6 but also works with IPv4. IPsec includes an Authentication Header (AH) using protocol ID number 51 and Encapsulation Security Payload (ESP) using protocol ID number 50. It uses the Internet Key Exchange (IKE) over UDP port 500 to create a security association for VPN.

Question 14

Secure File Transfer Protocol (SFTP)

Answer 14

Secure file transfer protocol (SFTP) is a secure implementation of file transfer protocol (FTP). It is an extension of SSH to transmit files in an encrypted format. SFTP transmits data using TCP port 22

Question 15

File Transfer Protocol Secure (FTPS)

Answer 15

File transfer protocol secure is an extension of file transfer protocol (FTP) and uses transport layer security (TLS) to encrypt FTP traffic. FTPS can use TCP port 989 and 990 or FTP ports 20 and 21.

Question 16

Simple Mail Transfer Protocol (SMTP)

Answer 16

Simple mail transfer protocol (SMTP) transfers email between clients and SMTP servers. SMTP uses TCP port 25.

Question 17

Post Office Protocol v3 (POP3)

Answer 17

Post office protocol v3 transfers or sends emails from servers down to clients. POP3 uses TCP port 110. Secure POP3 encrypts the transmission with SSL or TLS and can use TCP port 995.

Question 18

Internet Message Access Protocol v4 (IMAP4)

Answer 18

Internet message access protocol v4 is used to store email on an email server. IMAP4 allows users to organize and manage email in folders on the server. IMAP4 uses TCP port 143. IMAP4 with SSL or TLS can use TCP port 993.

Question 19

Domain Name System (DNS)

Answer 19

Domain name system is used for domain name resolution. DNS resolves host names, such as yahoo.com, to IP addresses. DNS uses UDP port 53 for queries. DNS servers can share information with each other by zone transfers using TCP port 53.