1.1 Protocols and ports

Question 1

Port do FTP servers listen for incoming traffic and send their own traffic.

Answer 1

Port 21

Question 2

what are network protcols

Answer 2

Network protocols are sets of rules and standards that define how devices communicate over a network.

Question 3

Protocols are used by devices to

Answer 3

send and receive different types of communication

Question 4

Segments are encapsulated in IP packets in which layer

Answer 4

3

Question 5

what does NIC stand for

Answer 5

Network interface card

Question 6

What is a network service

Answer 6

Provide a service
DHCP
DNS
MAIL SERVICE

Question 7

What is a Apache

Answer 7

A web server. HTTP

Question 8

SSL stands for

Answer 8

secure sockets layer

encryption-based Internet security protocol. Its main purposes are to provide privacy, authentication, and data integrity in Internet communications. SSL is the predecessor to the modern TLS (Transport Layer Security) encryption used today.

Question 9

what does tls stand for

Answer 9

transport layer security It is a cryptographic protocol used to secure data sent over a network, such as internet traffic.

Question 10

which layers do TCP and UDP segments send data from

Answer 10

layer 5, 6, and 7

Question 11

IMAP stands for

Answer 11

Internet message access protocol

Question 12

RTSP stands for

Answer 12

Real time streaming protocal.
Ensures data processed in the correct order.
UDP.Port 544

Question 13

How does three way handshake work

Answer 13

A TCP feature.
Synronication - meaning two devices send a message stating that they are ready to send and receive data packets.
Acknowledgement- both devices send announcements that they have authenticated with each other and ready to being data transmission.
Transmission of data begins.
syn, syn ack, ack.

Question 14

what four simple fields to UDP headers contain

Answer 14

source port, destination port, packet length (header and data), and a simple (and optional) checksum

Question 15

what is a packet

Answer 15

Network layer pdu.

Question 16

ICMP is used for

Answer 16

Utilites like ping and tracert/traceroute to provide control info to IP.

Question 17

what three fields do ICMP headers start with

Answer 17

type, code and checksum

Question 18

explain differences between tcp and udp

Answer 18

TCP - Accurate - connection-oriented, can’t lose packets, logical. UDP - Efficient, connectionless, can lose packets, quick performance.

Question 19

well known port numbers

Answer 19

0-1023 used by major protocls and services

Question 20

what does a port # do?

Answer 20

Gets data to the right applicaiton.

Question 21

ports 1024 to 49151

Answer 21

Reserved ports assigned by IANA to specific companies that want a common port to be used for their programs or protocols.

Question 22

49512 to 65535

Answer 22

Dynamic ports. Not assigned controled or registured. Used by client applications on an as needed basis.

Question 23

which has more overhead, and which strives for accuracy and which integrity and one striving for efficiency.

Answer 23

TCP and UDP

Question 24

What makes TCP have more overhead

Answer 24

3 way handshake and akmolw

Question 25

what is checksum

Answer 25

Used for error detection.

Question 26

two types of ICMP messages?

Answer 26

info messages and error messages

Question 27

What is flow control.

Answer 27

TCP will use technique called Buffer Space. As data is sent over tcp protocol the receiving device will send the sending device the amount of available space it has on its end to receive data. Allows sending device to send data at approate rate.

Question 28

Error checking

Answer 28

TCP feature called a Checksum. Checksum is an algorithm within each Data packet will be verified at the receiving device. If there is any type of modification to the checksum. then we know the data been modifed somewhere across the transmission path.

Question 29

Name four features of TCP

Answer 29

Error checking, reassembly, flow control and full duplex.

Question 30

Reassembly

Answer 30

When tcp sends packets across the network they are broken down into smaller units called segments. At the destination device all data packets are reassembled into their original form.

Question 31

what is Full duplex

Answer 31

data can be sent and received at the same time.

Question 32

Connection less protocol.

Answer 32

UDP. It does not have defined connection period.

Question 33

What does UDP support that TCP does not support

Answer 33

Broadcasting and Multicasting.

Question 34

What does UDP not have compared to TCP

Answer 34

Flow control, error checking, data reliably.

Question 35

What is broadcasting.

Answer 35

Single data packet can be sent to all devices on network segment.

Question 36

multicasting.

Answer 36

data can be sent to either one device or Mutiple users devices or users of your choosing.

Question 37

UDP is used for:

Answer 37

Services that require a consistently open protocol. DHCP VOIP Video streaming, online gaming

Question 38

IPsec

Answer 38

Internet Protocol Security, is a set of protocols designed to secure internet communication.

Question 39

Name two components of IPsec

Answer 39

autheincation header (AH) and security payload. (AH) provides authentication and integrity verification for an entire IP data packet. Security Payload (encapsuling) (ESP)

Question 40

ESP

Answer 40

Encapsulating Security Payload. It’s a protocol used within IPsec to provide a secure path for data to travel across the internet or other networks.

Question 41

Name two modes of IPSec

Answer 41

IPSec operates in two main modes, each designed for different security needs. Here’s a simple explanation of each: Transport Mode: Imagine sending a private letter to a friend. In transport mode, the contents of the letter (the payload) are sealed and secure, but the envelope (the IP header) is visible, showing where it’s going. This mode is typically used for end-to-end communication between two computers. Tunnel Mode: Now, think of sending a letter within another package. In tunnel mode, not only is the letter’s content secure, but the envelope is also hidden inside another envelope. This mode is used for network-to-network communications, like between two offices, where the entire original IP packet is encrypted and encapsulated within a new IP packet12

Question 42

Three common protocol types used for data transmission.

Answer 42

TCP, UDP IPSec

Question 43

DHCP Lease

Answer 43

How long IP address can be used before it's released back into pool.

Question 44

What does ESP do

Answer 44

Encapsulating Security Payload (ESP) It encapsulates It encrypts It also checks that the data hasn’t been changed along the way.

Question 45

GRE

Answer 45

Generic Routing Encapsulation

Question 46

What does GRE do

Answer 46

It's a tunnelling protocol capable of encapsulating a wide variety of network layer protocols.

Question 47

PPTP

Answer 47

Older tech VPN. Supports dial up VPN connections.

Question 48

Name a VPN Protocol

Answer 48

TLS

Question 49

Which layer does TLS work

Answer 49

Layer 5 and above

Question 50

IPSec works at which layer of the

Answer 50

layer 3 and above.

Question 51

Why doesn’t TLS work on layers 1-4

Answer 51

- **Lower layers (1-4)** focus on the physical transmission of data, routing, and error handling. They do not handle the aspects of session management, encryption, and application-specific requirements that TLS addresses. - **Layer 4 (Transport Layer)** already has protocols like TCP and UDP managing data transport, but they do not inherently provide encryption and security features that TLS adds on top. By operating at layer 5 and above, TLS can provide a comprehensive security solution that includes encryption, data integrity, and authentication, ensuring secure end-to-end communication for applications.