networks Flashcards
what is a network?
devices connected together that can exchange data and share resources with each other
what does LAN stand for?
local area network
what is a LAN?
network that covers a small geographical area located on a single site
all the hardware for a LAN is located by the organisation that uses it
examples of LANs?
schools
businesses
universities
what does WAN stand for?
wide area network
what is a WAN?
a network that connects LANs from different geographical locations
example of a WAN?
a business with offices in three different countries would need a WAN
why use a LAN/WAN?
sharing files is easier
share the same hardware (printers etc)
internet connection can be shared
user accounts stored so you can log in on any device on the network
hardware that makes up a network?
switch
router
network interface controller (NIC)
what is a switch?
they connect devices on a LAN
receive data from one device and transmit this data on the same network with the correct MAC address
what is a router?
transmit data between networks
direct packets to their destination
what is a network interface controller? (NIC)
internal piece of hardware that allows a device to connect to a network
what is an ethernet network?
a wired network
example of ethernet cables?
copper cables
coaxial cables
fibre optic cables
what is a copper cable?
twisted pair of cables containing 4 pairs of copper wires
reduces internal interference
what is a coaxial cable?
single copper wire surrounded by a plastic layer and metallic mesh
provides shielding from outside interference
what is a fibre optic cable?
transmit data as light
high performance over large distances
dont suffer interference
expencive
what is a wireless network
uses radio waves to transmit data between devices
advantages of wireless networks?
more convenient as you can move around and stay connected
cheaper as fewer wires
wireless network topologies?
bluetooth
wi-fi
what is bluetooth?
a direct connection between two devices so data can be shared
short range of connection
low bandwidth
often used between phones
what is wi-fi?
can be used by multiple devices to connect to a LAN at the same time
larger range of connection
high bandwidth
often used at home
what is a wireless access point? (WAP)
a switch that allows devices to connect wirelessly (for wi-fi)
what is a client server network?
a network managed by a SERVER which connects to devices called CLIENTS
what do clients do on a client server network?
request data from the server
what do servers do on a client server network?
process requests from clients and respond
what does a client server network store?
user profiles
passwords
access information
advantages of a client server network?
easy to keep track of files as they are stored centrally
easy to perform backups and update software
easy to manage network security
disadvantages of client server networks?
expensive to set up and needs maintenance by IT specialists
if the server goes down all clients lose access to their work
server can become overloaded if too many requests are sent at once
what is a peer to peer network?
they connect directly to each other without a server
advantages of a peer to peer network?
easy to maintain
no dependance on a server if one fail the whole network isnt lost
disadvantages of a peer to peer network?
updates have to be done individually
less reliable
device slows down when another accesses ut
what is a topology?
the layout of a network
what is a star topology?
all the devices are connected to a central switch or server that controls the network
advantages of star topology?
if one device fails the rest are fine
easy to add more devices
better performance, goes straight to the central device
disadvantages of a star topology?
in a wired star every device needs a cable to the central device
expensive for wires if theres lots of devices
if the server/switch goes down, it all stops
what is a mesh topology?
all devices are connected without a server/switch in the centre
data is sent along the fastest route
advantages of mesh network?
if one goes down the data gets sent along a different route
disadvantages of mesh topology?
its expensive, requires lots of wires
what is a full mesh?
all devices connect together
what is a partial mesh?
not all devices are fully connected
what is a network standard?
agreed requirements for hardware and software
why are network standards important?
allow manufacturers to create products and programs that will be compatible with others
what is a network protocol?
a set of rules for hoe devices communicate and how data is transmitted across a network
what is a MAC address?
they are unique, cannot be changed and assigned to every device by the manufacturer
what id an IP address?
used when sending data between networks
assigned either manually or automatically before the device can access the network
what is the internet?
a network of networks, a huge WAN which connects networks from all over the world
what is a domain name service? (DNS)
used to translate website domain names into IP addresses
what is the cloud?
uses the internet to store files and applications
advantages of the cloud?
can access through any connected device
easy to increase storage
updates automatically
disadvantages of the cloud?
needs connection to the internet
dependent on host
can be vulnerable to hackers
what is an insider attack?
someone within the organisation exploits their network access to steal info
what is a brute force attack?
use of automated software to crack passwords through trial and error
what is a denial of service attack? (DoS)
flooding the network with useless requests making the network extremely slow or completely inaccessible
what is phishing?
emails, texts, calls trying to get infi
what is malware?
malicious software
can be installed on a device without consent
examples of malware?
locking files
deleting files
spyware - monitors actions
opening backdoors for future hacking
what are the three ways malware can access a device?
viruses
worms
trojans
what is a virus?
attach to files and users spread them by copying infected files and activate them by opening said files
what are worms?
they self replicate without user help meaning they spread really quickly
what are trojans?
malware disguised as legitimate software, users install them not realising their hidden purpose
what is social engineering?
a way of getting information by influencing people, typically over the phone
what is SQL injections?
SQL - structured query language
(main coding language)
pieces of SQL typed into a websites input box which reveals information
SELECT, WHERE
types of prevention?
penetration testing
encryption
firewall
anti malware software
strong passwords
what is penetration testing?
when organisations purposefully hack their own networks to reveal weak areas
what is physical security?
protects the physical parts of a network from damage
examples of physical security?
locks
CCTV
passcode doors
motion sensors
what is anti malware software?
designed to find and stop malware from damaging a network and the connected devices
example of anti malware software?
firewalls - examine all data entering and leaving the network
anti virus - isolate and destroy viruses
what is encryption?
translating data into code where only somebody with the correct key can access it
