Module 3

Question 1

Ports

Answer 1

A # used to uniquely identify network connection & specify services as apps that is destined 4

Question 2

Open Ports

Answer 2

Means a device is listening or talking. If unused it can be a security risk in which the router will attempt to keep close aka firewall.

Question 3

Well Known Ports

Answer 3

Ports that are already reserved (0 - 1023). Mostly owned by big tech firms.

Question 4

Registered Ports

Answer 4

ports that can be registered with companies through (IANA) ( 1024 - 49,151)

Question 5

Private Ports

Answer 5

ports ( 49,152 - 65535) that can be used by anyone

Question 6

Internet Assigned Numbers Authority - IANA

Answer 6

Organization that assigns ports & IP addresses to companies as well search for information on ports.

Question 7

Transmission Control Protocol - TCP

Answer 7

it is connection-oriented makes sure there is a 3-way handshake. Aka TCP segment. Favors safety over speed & has Sequence & acknowledgment #s.

Question 8

TCP Cont.

Answer 8

1. Orders the stream.
2. Detects errors & connections.
3. Flow control has a sliding window to control the amount of segment coming in or out.
4. Congestion Control.
5. Complex & heavyweights.

Question 9

TCP Connection Establishment

Answer 9

1. Source computer send SYN
2. Destination Computer send an SYN + ACK.
3. Source computer sends ACK.

Question 10

TCP Connection Termination

Answer 10

1. Device timeout or turns off.
2. Source computer sends a FIN.
3. Destination computers send ACK.
4. Destination computer sends FIN + ACK.
5. Source computer send ACK.
   (Session Closed)

Question 11

User Datagram Protocol - UDP

Answer 11

Gets there if it gets there. Called a UDP datagram. Favors speed over safety and has unreliable delivery. Used when loss can be tolerated. Has length & checksum. It is lightweight & fast, not ordered, and no congestion control.

Question 12

NETSTAT

Answer 12

(-a, -b, -n, -o,-r) to know more information about the traffic happening in your network.

Question 13

Port Forwarding - PF

Answer 13

Any traffic arriving on a specific TCP or UDP port will forward 2 a defined internal host & port. Punches a hole in firewall- FW

Question 14

Domain Name System - DNS

Answer 14

resolves IP address based on Fully Qualified Domain Names (FQDNs). Lets us visits websites without knowing the long IP address #.

Question 15

Nslookup

Answer 15

Used in command prompt/powershell to find the IP @.

Question 16

Fully Qualified Domain Names - (FQDNs)

Answer 16

identifies the specific server or host @ the Domain. Ex: www.google.com

Question 17

Uniform Resource Locator - URL

Answer 17

Includes the FQDNS & protocol such as HTTP, HTTPS, & FTP.

Question 18

Public DNS Server

Answer 18

a free 2 use DNS server on the public internet. Resolves public FQDNs 2 IP addresses. ISP have their own DNS server.

Question 19

Private DNS Server

Answer 19

Provides internal hostname lookups within a private organization. These names are not part of the public DNS server and are associated w/ an organizations private IP address.

Question 20

Split Horizon DNS aka Split Brain

Answer 20

A mechanism 4 DNS server 2 supply different results based on the source. When a company hosts their own website with public facing DNS. Web will use DNS to lookup up internal private IP addresses to provide to the public facing DNS to website.

Question 21

Secure Shell - SSH

Answer 21

command line access to network nodes. Sessions are encrypted best to use v2 and replaces protocols like Telnet.

Question 22

Dynamic DNS - DDNS

Answer 22

is a method of automatically updating a name server in the Domain Name System (DNS), often in real-time, with the active DDNS configuration of its configured hostnames addresses or other information.

Question 23

TELNET

Answer 23

similar to SSH but unsecure. Can see clear/plain texts even passwords. Best to be disabled.

Question 24

Internet control Messaging Protocol - ICMP

Answer 24

Checks IP connectivity 2 any network node uses ping (echo request & echo reply). Works at L3 so no port#. traceroutes uses it but org. block to prevent DoS attacks.

Question 25

Virtual Terminal Lines - VTY

Answer 25

mostly used 2 configure devices in the network.

Question 26

File transfer Protocol - FTP

Answer 26

used to retrieve/transfer files from an FTP server on the network. It is connection oriented, work on ports 20 - FTP & 21 - FTP Data.

Question 27

Trivial FTP

Answer 27

is a simple protocol for transferring files, connectionless, implemented on top of the UDP/IP protocols using well-known port# 69.

Question 28

Open Systems Interconnected Devices - OSI Model

Answer 28

``` the International Standards Organization (ISO) developed a conceptual model as a way to reference inter computer communication processes. This 7 layer visual model was developed in 1984. 1. Application 2. Presentation 3. Session 4. Transport 5. Network 6. Data Link 7. Physical ```

Question 29

OSI - Application Layer 7

Answer 29

Application services for end user processes such as file transfers, email, remote terminal access, domain name resolution, web transfer, network management etc. Protocols such as FTP & Telnet.

Question 30

OSI - Presentation Layer 6

Answer 30

Provides translation to/from the application layer. Performs data encryption, decryption, compression and decompression. Associated with file formats such as JPEG, MPEG etc.

Question 31

OSI - Session Layer 5

Answer 31

Coordinates, establishes, manages and tears down sessions between applications on either side of the connection. Maintains separate sessions for the different applications data streams.

Question 32

OSI - Transport L4

Answer 32

Segments and reassembles data from upper layers and unites them into the same data stream. Provides flow control for data loss prevention as well as reliable and unreliable transport methods.

Question 33

OSI - Network L3

Answer 33

Provides logical network addressing and path determination/routing services. Responsible for packet delivery, fragmentation, and sequencing. This is the layer where Internet Protocol resides.

Question 34

OSI - Data Link L2

Answer 34

LLC & MAC

Question 35

Logical link Control - LLC

Answer 35

includes the Logical Link Control (LLC) sublayer which provides error detection and control.

Question 36

Media Access Control - MAC

Answer 36

delivers frames using unique hardware addressing via the Media Access Control (MAC) sublayer.

Question 37

OSI - Physical L1

Answer 37

Turns raw bits into electrical signaling and defines physical network media such as copper cabling, fiber optics, and wireless transmission standards. Concerned with bit rates and transmission modes.

Question 38

Protocol Data Unit - PDU

Answer 38

is used to describe the data as it moves through each layer. ex. Data (L7-5), Segment (L4), Packet (L3), Frame (L2), & Bits (L1)

Question 39

Transport Layer Security - TLS

Answer 39

TLS is a cryptographic protocol that provides end-to-end communications security over networks and is widely used for internet communications and online transactions (IETF standard).

Question 40

Secure Socket Layer - SSL

Answer 40

is a networking protocol designed for securing connections between web clients and web servers over an insecure network, such as the internet.

Question 41

Network Basic Input/Output System - NetBIOS

Answer 41

file & network sharing and of old age.

Question 42

Password Authentication Protocol - PAP

Answer 42

is a password-based authentication protocol used by Point to Point Protocol (PPP) to validate users. It is unsecure yet supported by all devices.

Question 43

Session Initiation Protocol - SIP

Answer 43

is a signaling protocol used for initiating, maintaining, and terminating real-time sessions that include voice, video and messaging applications. Part of VoIP.

Question 44

Real-time Protocol - RTP

Answer 44

responsible for delivering audio and video over IP networks.

Question 45

Encapsulating Security Payload - ESP

Answer 45

is a protocol within the IPSec for providing authentication, integrity and confidentially of network packets data/payload in IPv4 and IPv6 networks.

Question 46

Enhanced Interior Gateway Routing Protocol - EIGRP

Answer 46

is an advanced distance-vector routing protocol that is used on computer networks for automating routing decisions and configuration.

Question 47

Open Shortest Path First - OSPF

Answer 47

is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS).

Question 48

Transmission Control Protocol/ Internet Protocol - TCP/IP

Answer 48

The TCP/IP model was created for referencing protocols in the TCP/IP stack. It does not include things like physical wire and transmission specifications such as Ethernet. Created by DARPA aka a DOD model. A similar representation of the OSI model. 1. Application 2. Transport 3. Internet 4. Network (Link Layer)

Question 49

Client to Server Model

Answer 49

client access resources via a centralized server. Server requires dedicated infrastructure & service.

Question 50

Peer 2 Peer - P2P

Answer 50

peers simply share information with each other. Sharing of resources is local and uses remote sharing programs like BitTorrent, Filetopic, & Gnutella. Peer host can be both client & server, resources are not centralized, & difficult 2 administrate for large networks.