Section Two - Networks Flashcards
What does LAN stand for?
Local Area Network
What does a LAN cover?
A small geographical area located on a single site
Give one reason why you should use a LAN:
Sharing files is easier - network users can access the same files, work collaboratively on them and copy between machines
What does WAN stand for?
Wide Area Network
What is the purpose of a WAN?
To connect LANs that are in different geographical locations
How can WANs be connected?
Through fibre or copper telephone lines, satellite links or radio links
Give an example of a WAN you use every day:
The Internet
What is Bandwidth?
The amount of data that can be transferred in a given time
Finish the sentence:
The greater the bandwidth, the…
…better the network can perform
True or False? Wired connections are generally SLOWER and LESS reliable than Wireless.
False.
Wired connections are generally FASTER and MORE reliable than Wireless
What does Wireless performance depend on?
Signal Quality
What factors affect Signal Quality?
Range of Device
Amount of inference from other devices
Physical Obstructions
What does NIC stand for?
Network Interference Controller
What is an NIC?
An internal piece of hardware that allows a device to connect to a network
What is the purpose of a switch in a LAN?
To connect devices
What are routers responsible for?
Transmitting data between networks
What can Ethernet cables be used for?
To connect devices in a LAN
Give examples of a type of Ethernet cable:
CAT 5
CAT 6
True or False? Ethernet Cables contain THREE twisted pairs of FIBRE-OPTIC wires.
False.
Ethernet Cables contain FOUR twisted pairs of COPPER wires.
Why are the wires in Ethernet cables twisted together?
To reduce internal interference
What are Coaxial cables made of?
A single copper wire surrounded by a plastic layer
What is the purpose of the plastic layer in Coaxial cables?
Insulation and shielding from outside inteference
How do fibre-optic cables transmit data?
Using light
True or False? Fibre-Optic cables are HIGH performance cables that DON’T suffer interference and CAN transmit over very large distances.
True
What do wireless devices use to transmit data?
Radio waves
What does WAP stand for?
Wireless Access Point
What could a WAP simply be described as?
A switch that allows devices to connect wirelessly
What radio frequency bands are used by Wi-Fi?
2.4Ghz and 5Ghz
Fill in the gaps:
1) networks are made up of a (2) and (3
(1) Client-server
(2) Sever
(3) Clients
What is a client-server network managed by?
A server
Describe a client-server relationship:
Clients send requests to the server. The serve processes the request and responds.
What are the PROS of a client-server network?`
Easy to keep track of files
Easy to perform back-ups
Easy to install and update software
Easy to manage security
What are the CONS of a client-server network?
Expensive to set up (needs specialists to maintain)
All clients lose access is server goes down
The server can be overloaded
True or False?
Peer-to-Peer networks USE servers.
False.
Peer-to-Peer networks DON’T use servers. Clients connect directly to each other without a server.
What are the PROS of a Peer-to-Peer network?
Easy to maintain
No dependence on server.
What are the CONS of a Peer-to-Peer network?
No centralized management
Less reliable
Slower
What is a topology?
The layout of a network.
Give two examples of topologies:
Star and Mesh
In a STAR topology, where are all the devices connected to?
A central switch or server that controls the network
True or False?
Star networks MAY be wired or wireless.
True.
What are the PROS of a Star Topology?
If a device fails, the rest of the network is unaffected.
Adding more devices is simple
Better performance than other set-ups.
What are the CONS of a Star Topology?
In wired networks, every device needs a cable. This makes it expensive.
If there is a problem with the switch or server the whole network is affected.
In a MESH topology, where are all the devices connected to?
They are all connected to each other.
It is decentralized - networking devices are directly or indirectly connected to every other device without a central switch or server.
What is the MAIN advantage of a mesh topology?
There is NO single point where the network can fail. If one device fails, data will just be sent along an alternative route.
What is the difference between a FULL MESH topology and a PARTIAL MESH topology?
A full mesh topology is where every device is connected to every other device. In a partial mesh topology, not all devices are fully connected.
Fill in the gaps: Networks need (1) to set the rules.
(1) Protocols
What is a protocol?
A set of rules for how devices communicate and how data is transmitted across a network.
When are MAC Addresses used?
When devices are communicating on the same network.
True or False?
MAC Addresses are unique to the device and cannot be changed.
True
What are MAC addresses made up of?
48 or 64-bit binary numbers. To make them easier they’re converted into hexadecimals.
When are IP Addresses used?
When devices are communicating between different networks.
Describe the difference between STATIC and DYNAMIC IP addresses:
Static IP addresses are permanent addresses. Dynamic IP addresses are assigned to the device by a network server, meaning your device may have a different IP address every time you log on to the network.
True or False?
IP addresses are 32-bit and CAN’T be 128 bit.
False.
IP addresses can either be a 32-bit or 128-bit binary number.
Fill in the gaps:
Data is sent between networks in (1).
(1) Packets
Describe the header of a packet:
Every data packet has a header - this contains control information. This information includes the packet’s destination address, the source address and the packet number.
What is the purpose of a checksum number in a packet?
A form of validation used to check that the payload data hasn’t been corrupted during transit.
What is PACKET SWITCHING used for?
It is used to direct the data.
Order the steps of PACKET SWITCHING:
A receipt confirmation is sent to the sending device
Each router reads the packet header and decides which way to send the packet.
The sending device splits the data into packets
The receiving device uses packet numbers to put them in the right order.
Each packet is given a packet number.
As the packets take different routes, they can arrive in the wrong order.
The sending device splits the data into packets
Each packet is given a packet number.
Each router reads the packet header and decides which way to send the packet.
As the packets take different routes, they can arrive in the wrong order.
The receiving device uses packet numbers to put them in the right order.
A receipt confirmation is sent to the sending device.
What are the two most important protocols?
TCP - Transmission Control Protocol
IP - Internet Protocol
What is the purpose of a TCP?
To set the rules for how devices connect on a network. It’s in charge of splitting data into packets and reassembling packets. It’s responsible for checking the data is correctly sent and delivered.
What is the purpose of an IP?
To control packet switching.
What does HTTP stand for and what is it used for?
Hyper Text Transfer Protocol
-Used by web browsers to access websites and communicate with web servers.
What does HTTPS stand for and what is it used for?
HTTP Secure
-A more secure version of HTTP. Encrypts all information sent and received.
What does FTP stand for and what is it used for?
File Transfer Protocol
-Used to access, edit and move files between devices on a network.
What does POP3 stand for and what is it used for?
Post Office Protocol - version 3
Used to retrieve emails from a server. The server holds the email until you download it, at which point it deletes it from the server.
What does IMAP stand for and what is it used for?
Internet Message Access Protocol
Used to retrieve emails from a server. The server holds the email until you actually delete it - you only download a copy.
What does SMTP stand for and what is it used for?
Simple Mail Transfer Protocol
Used to send emails. Also used to transfer emails between servers.
What are the four layers of Network Protocols?
Application Layer
Transport Layer
Network Layer
Data Link Layer
What is the fourth layer?
Application Layer
What do protocols in the fourth layer cover?
Turning data into websites and other applications and vice versa.
What are examples of protocols in the fourth layer?
HTTP, FTP, SMTP
What is the third layer?
Transport Layer
What do protocols in the third layer cover?
Controlling data flow
What are examples of protocols in the third layer?
TCP
What is the second layer?
Network Layer
What do protocols in the second layer cover?
Making connections between networks, directing data packets and handling traffic. Used by routers.
What are examples of protocols in the second layer?
IP
What is the first layer?
Data Link Layer
What do protocols in the first layer cover?
Passing data over the physical network. Responsible for how bits are sent as electrical signals over cables, wireless and other hardware.
What are the advantages of using layers?
- Breaks network communications into manageable pieces.
- Layers can be changed without other layers being affected
Fill in the Gaps:
The Internet is a (1) collection of (2)
(1) Worldwide
(2) networks
What protocol is the Internet based around?
TCP/IP
True or False?
The World Wide Web is a collection of websites that are hosted on web servers.
True
They are accessed through the HTTP protocol.
Complete the sentence:
A Domain Name Serve translates a website’s domain name into…
..its IP address. The internet has a network of Domain Name Servers.
What is Hosting?
When a business uses its servers to store files of another organisation.
What are the advantages of The Cloud?
- Easily access files
- Easy to increase storage
- No expensive hardware
- No maintenance fee
- Security and back-ups provided
- Updated automatically
What are the disadvantages of The Cloud?
- Need access to Internet
- Dependent on Host
- Data vulnerable to hackers
- Subscription fees
Fill in the Gaps:
A (1) network that is entirely (2)-based.
(1) virtual
(2) software
How are Virtual Networks created?
Virtual Networks are created by partitioning off some of a physical network’s bandwidth to form a separate network.
What is the impact of Virtual Networks having there own security?
Virtual Networks can only be accessed by using certain software or login information.
What does VPN stand for?
Virtual Private Network
What is a VPN?
A type of virtual network that can be used to send data securely over a large network.
What is a PASSIVE attack?
Where someone will monitor data travelling on a network and intercepts any sensitive information they find.
What is the best DEFENCE against PASSIVE attacks?
Data Encryption
What is an ACTIVE attack?
When someone attacks a network with malware or other planned attacks.
What is the main DEFENCE against an ACTIVE attack?
A Firewall
What is an INSIDER attack?
Where someone within an organisation exploits their network access to steal information.
What is a BRUTE FORCE attack?
A type of active attack used to gain information by cracking passwords through trial-and-error.
What measures REDUCE the risk of a BRUTE FORCE attack?
Locking accounts after a certain number of attempts
Strong Passwords
What is a DENIAL-OF-SERVICE attack?
Where a hacker tries to stop users from accessing a part of a network or website.
What do most DENIAL-OF-SERVICE attacks involve?
Flooding the network with useless traffic, making the network extremely slow or completely inaccessible.
What is Malware?
Software that can harm devices.
It is installed on someone’s device without their knowledge or consent.
What are typical actions of malware?
Deleting/Modifying files.
Scareware
Locking Files
Spyware
What is Social Engineering?
A way of gaining sensitive information or illegal access to networks by influencing people.
What is Phishing?
Phishing is when criminals send emails or texts to people claiming to be from a well-known business.
Fill in the gaps:
(1) Injections give criminals easy access to (2) data.
(1) SQL
(2) Insecure
What does SQL stand for?
Structured Query Language
What are SQL injections?
Pieces of SQL typed into a website’s input box which then reveal sensitive information
What is the coding language of SQL used for?
To access information in databases
What is an issue of a website’s SQL code not having a strong enough input validation?
Someone may be able to enter a piece of SQL code which allows them to access other people’s account information.
What are the properties of a GOOD network policy?
Regularly test the network to find and fix security weaknesses
Use passwords to prevent unauthorised access
Enforce user access levels
Install anti-malware and firewall software
Encrypt sensitive data
What is penetration testing?
When organisations employ specialists to stimulate potential attacks on a network.
What is penetration testing used for?
To identify possible weaknesses in a network’s security and trying to exploit them.
What are network forensics?
Investigations undertaken to find the cause of attacks on a network.
What do organisations need to conduct network forensics?
A system of capturing data packets as they enter their network.
What are network forensics used for?
To analyse packets after attacks to discover how the network was attacked and decide how to prevent future attacks.
What is the purpose of passwords?
To help prevent unauthorised users accessing the networks.
What is the purpose of User Access Levels?
To control which part of the network different groups can access
What type of attack do User Access Levels help prevent? Give Reasons.
Insider Attacks because they help limit the number of people with access to important data.
What is the purpose of Anti-Malware software?
To find and stop malware.
What is Encryption?
When data is translated into a code which only someone with the correct key can access.
What is encrypted text called?
Cipher text
