AP networking test

cd~

takes to home directory

cd /

takes to root directory

cd home

takes to a home directory

cd ..

moves up one

ls

list files

pwd

working directory

cd

change directory

mkdir

create new directory

cp

copy files

mv

move or rename files

touch

create empty files

cat

view file components

whoami

displays the current user

NIC

Network Interface Cards carries the data such as copper wire

a network node

any device connected to a network

host

devices that send or receive data

8 bits

a bythe

PAN

Personal Area Network like bluetooth to connect mice, keyboards, and tablets

LAN

local area network consists of a switch and network devices in a limited geographical area.

VLAN

virtual LAN extends beyond a traditional LAN and groups uses based on administratively defined boundaries

WLAN

wireless LAN connects multiple wireless access points together to expand a wireless network

WMN

wireless mesh network connects multiple wireless access points together to expand the wireless network

MAN

metropolitan area network a network that spans a city

WAN

wide area network a network that spans a large geographical area.

VPN

Virtual Private Network a method of connecting to a network such as a company network across an unsecured network

twisted pair

(such as cat5 and cat6) is electrical (copper) low cost.

coaxial cable

(shielded) electric (copper) medium cost

Fiber optic

Light (glass or plastic) high cost CAN NOT BE INTERFERED WITH ELECTRIC

layer 1

physical layer

layer 2

data link layer

layer 3

network layer

layer 4

Transport Layer

layer 5

Session Layer

layer 6

Presentation Layer

layer 7

Application Layer

Star Topology

A topology with one central node that has each computer or network device attached to the central node. All data first goes into the central node and then is sent out to its destination. (Think of it like a bicycle wheel with spokes.)

Mesh Topology

Devices are connected with many redundant interconnections between network nodes.

Bus Topology

A network layout in which there is one main trunk, or backbone, that all the various computers and network devices are connected to.

Hybrid Topology

A physical topology that combines characteristics of more than one simple physical topology.

Physical Topology

The physical arrangement of connections between computers.

logical topology

A topology that describes the data-flow

patterns in a network.

Encapsulation

wrapping data with headers as it travels down the OSI layer

decapsulation

Removing a header or trailer from a lower OSI layer.

example of layer 1

physical cables, hubs, or signals

example of a layer 2 device

switch

example of a layer 3 device

router

ifconfig

finds MAC adress

Confidentiality

Only authorized users can access specific assets or data

integrity

protecting data from unauthorized alteration

availability

authorized users ALWAYS have access to

DRM

Digital Rights Management - application of control technologies to limit the use of digital media

IRM

Information Rights Management used with email and other files that are related to communication of an organization

spoofing

a technique intruders use to make their network or internet transmission appear legitimate to a victim computer or network

flooding

an attack where a malicious actor overwhelms a network switch with a large number of MAC addresses

CAM

Content Addressable Memory table routes where to send traffic

administrative controls

Policies, procedures, security awareness training, contingency planning, and disaster recovery plans

Technical Controls

hardware/software implementad to manage and provide protection

Preventative Controls

can block someone from proforming a malicious action

physical control

designed to protect facilities, systems, and resources and separate people physically from systems

detective controls

controls designed to discover control problems that were not prevented

corrective controls

brings a system back to it's normal state

Deterrent Controls

discourage attackers from preforming malicious acts

Recovery Controls

works with corrective to bring back to normal state

Public IP Address

anyone on the internet can see it, anyone connected to the internet has one, cannot be repeated

ISP

(Internet Service Provider) A company that provides access to the Internet.

Private IP address

An IP address that cannot be routed over the Internet allows devices within the network to talk without using internet

NAT

Network Address Translation is a process that the router uses to act like a translator, takes private IPs and uses public IP to send and receive information from websites

PAT

Port Address Translation. A form of NAT that translates public IP addresses to private IP addresses, and private IP addresses back to public IP addresses. PAT uses a single public IP address. Compare to DNAT.

data path

the specific sequence of devices and physical links that a packet follows from a source to a destination

routing table

A data table stored in a router that lists the routes to particular network destinations

Hop

each time a packet goes through a router

TTL

(Time to Live) every time a packet takes a hop a number in its header gets deleted- this prevents packets from hoping forever

TCP

Transmission Control Protocol - provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

UDP

User Datagram Protocol. Used instead of TCP when guaranteed delivery of each packet is not necessary. UDP uses a best-effort delivery mechanism.

Subnetting

The act of dividing a network into smaller logical subnetworks.

what does the physical layer do?

media, signal, binary transmission

What does the data link layer do?

The data link layer controls the way messages are sent on the physical media. The data link layer handles three functions: media access control, message delineation, and error control. The data link layer accepts messages from the network layer and controls the hardware that actually transmits them. The data link layer is responsible for getting a message from one computer to another without errors. The data link layer also accepts streams of bits from the physical layer and organizes them into coherent messages that it passes to the network layer.

What does the network layer do?

path determination and IP address

what does the transport layer do?

Responsible for preparing data to be transported across the network

what does the session layer do?

It keeps data from different applications separate, reliably

what does the presentation layer do?

deals with formatting of data and encryption.

what does the application layer do.

Provides access to network resources

what is the PDU of the physical layer?

bits

What is the PDU at the Data Link Layer?

frames

what is the PDU of the network layer

packets

What is the PDU at the Transport layer?

segments

what is the PDU of the session layer

data

what is the PDU of the presentation layer

data

what is the PDU of the application layer

data

what acronym can be used to remember the OSI layers?

please (presentation)

do (data link)

not (network)

throw (transport)

sausage (session)

pizza(presentation)

away (application)

what is HTTPS protocol

Hyper Text Transfer Protocol Secure - encrypts all info sent and received (a more secure version of HTTP)

DNS Protocol

query and reply messages, both with same message format (port 53)

DHCP Protocol

assigns IP addresses

FTP

File Transfer Protocol

Private IP Ranges

10.0.0.0 - 10.255.255.255

172.16.0.0 -172.31.255.255

192.168.0.0-192.168.255.255

router

directs traffic between networks

switch

A device for making, breaking, or changing the connections in an electrical circuit (MAC address)

firewall

a part of a computer system or network that is designed to block unauthorized access while permitting outward communication.

modem

Communications hardware device that facilitates the transmission of data.

what is the troubleshooting protocol

identify problem

test

fix

verify