1.3.3 network Flashcards
missing network hardware
standalone machine
computer that is not connected to anything
stopping the spread of a virus on hardwares(unknown memory sticks)
network
a group of devices connected to each other and can communicate with each other
internet
inter connected networks- global network of computers connected together (network of networks)
www
collection of webpages
protocol
RULES that govern how devices COMMUNICATION with each other(standard)
use of protocol layering
DECOMPOSITION-Reducing a complex problem into smaller sub-problems.
ABSTRACTION FOR SPECIFIC FUNCTION-Devices can be manufactured to operate at a particular layer.
COMPATABILITY-Products from different vendors will work together.
TCP/IP Stack
used in the routing of packets through networks
how it works:
Data is split into chunks called packets
(1 – AO1.1) which have labels (1 –
AO1.1) including address being sent to
(1 – AO1.1) and order (1 – AO1.1).
Each packet is sent on the most
convenient / avoidable route (1 –
AO1.2) meaning they may arrive in a
different order to which they were sent
(1 – AO1.2). Once packets arrive at
receiver they are reordered (1 –
AO1.2).
TCP
Transmission Control Protocol – used with IP to ensure ERROR FREE transmission and package switching
establish an end-to-end connection between the source and recipient computer
IP
Internet Protocol – used to transfer all packets across the internet between routers
DNS
use of system: name and organise internet resources
DNS server: that stores a list of domain names and translate them into associated IP addresses (ISP)
TLD: org/uk/com
SLD: google/edgbarrow
LAN
size of area: small, one site
ownership of hardware: by the organisation using it
link: UTP cable, fiber optic , wifi
WAN
size of area: larger geographical area (>1 sq mile)
ownership of hardware: connect to LANs, telecommunication companies who own and manage it.
link: telephone lines, fiber optics cables, satellite links
UTP
link layer- one less layer of shield
STP
link layer- one more layer of shield
packet switching
Splitting data into packets that can be sends individually across different routes across a network
circuit switching
Reserving a particular network route to transfer data between two devices
SMTP
outbound:
simple mail transfer protocol-
FORWARD the mail to the appropriate mail server
(the SMTP server has the database of email address)for the recipient’s email address
IMAP
inbound:
internet message access protocol - keep emails on mail server
(allow flagging and searching, can sync devices, less privacy )
POP
inbound:
post office protocol- deletes email from mail server once it is downloaded
(removes the mail from other devices, cannot do complex searches and flagging mail)
switch
Network device that connects multiple devices together, sending the data that it receives to the intended recipient device only
hub
Network device that connects multiple devices together, sending the data that it receives to all connected devices
router
Network device that directs data from one network to another
MAC vs IP
MAC: individual device
IP: the location/general area for destination
TLD
top level domain - e.g. .org, .uk, .com, .edu, .gov
SLD
second level domain - e.g. google
FTP
file transmission protocol- handles file uploads and downloads (works at the back end), normally on WAN
HTTP, HTTPS
for client and server to send and receive requests and deliver HTML web pages
(s): secure - encryption and authentication
UDP
user datagram protocol- simple connectionless transmission model
protocol layering
application
transport
network
link
the area/purposes of protocol
email(SMTP,IMAP,POP)
webpage request(HTTP,HTTPS)
file transfer (FTP)
LAN/WAN (TCP/IP, UDP)
client to server model
one device (the client) requests services from another device (the server).
peer to peer model
all terminals have equal status and there is no powerful central server, each computer acts as both a client and a server.
switch(vs hub) vs router
a switch connects multiple devices to create a network, a router connects multiple switches, and their respective networks, to form an even larger network
(links) Fibre Optic Cables
newer, faster and high-capacity
firewall
Security measure that controls incoming and outgoing network traffic using a set of rules (ports)
act as filter
mechanism of firewall:
-proxy
-inspection and packet filtering
proxies
A proxy ensures there is no direct physical connection between a single user and a remote source.
encryption
A method of transforming data into an unintelligible way so that it cannot be read by unauthorised individuals.
malware
malicious software - software that annoys users or damages their data. For example, Worms, Viruses, Trojans and Spyware.
worm
standalone
copies itself
virus
copies itself by attaching itself to another program
trojan
looks innocent but has ill intent
open up back doors
social engineering
involves with “social” and human interaction
-smishing : fake text messages
-vishing: fake voice call
-pharming : fake websites
phishing
use of email to take the user to a fake website to take their personal information
SQL injections
code enter to input text boxes
prevention: sanitisation and by blocking certain characters
ransomeware
blackmail(scare users) into making a payment
most vulnerable with social engineering
the elderly
the youngs
people not familiar with technology
spyware
designed to collect information about what you are doing on the computer
e.g. keylogger
there are also hackers that hack cameras and mics
anti-malware vs anti-virus
COVERAGE
anti-malware: designed to log keys(keylogger) and target adverts(adware) + virus
anti-virus: ‘quarantine’ the file so it cannot be used to spread the virus; does not cover malware
hackers
black hat
grey hat
white hat
DOS and DDOS
sending requests after requests to affect server performance
denial of service- one attacker using one/ more devices
distributed denial of service- uses botnet
network security methods
-username and password
-acceptance usage policy
-penetration testing
-physical security
-user access levels
cards included:
-firewalls
-encryption
