Networks Flashcards
Name the two types of Networking Conceptual Models
OSI “Open System Interconnect” and TCP/IP “ Transfer Control Protocol/ Internet Protocol”
Name the layers present in the OSI model
- Application
- Presentation
- Session
- Transport
- Network
- Data link
- Physical
Name the layers included in the TCP/IP model
- Application
- Transport
- Internet
- network
What does the Application level do??
Computer Interaction level in which the user can interact with the data present.
What does the Presentation level do??
“Compression/ Decompression”
Data encryption change data packets into a useable format.
What does the Session level do??
“Timing”
Maintains the connections, and is responsible for controlling the parts/ sessions. Makes sure the data can get accessed by the user.
What does the Transport level do??
Transmits data using transmission protocols including TCP and UDP.
What does the Network Link level do??
Defines the path that the data will take.
What does the Data Link level do??
Defines the format of data on the network.
E.g. JPEG or GIF
What does the Physical level do??
Transmits raw bit data.
What Layers make the data into Packets or Streams??
- Transport Layer
- Network Link
- Data Link Level
Define “Vulnerability”
A weakness a system already has.
Define “Threat”
Something that could happen because of a vulnerability.
Name the most important IP addresses
FTP Data: 20
FTP Control: 21
HTTP: 80
HTTPS: 443
What is a “Port Number”??
A set of numbers that defines a software or protocol.
E.g. 80 for HTTP
It tells a Computer what Application to send the data too.
What is an “IP Address”??
A set of numbers that define a Server or Device.
It tells a Network to connect to a specific device.
List the features of a Firewall
- Network Security System
- It creates a barrier for personal devices
- They filter legitimate data from Mal. data
- Doesn’t work with encrypted data
- Can be Hardware and Software
What is a “Proxy Server”??
Servers that can confuse harmful data. It does this by performing fake actions.
Like a Server Cloak.
List some Network Vulnerabilities
- Hackers can see what ports are being most used E.g. Port 80, then it can be attacked
- External Storage Devices can be used to bring Mal. code into a network.
- Ports can be Open and Unsecure, meaning all ports are at risk of being hacked. A Firewall can block any unused ports to increase security.
Define “Network Access Control” (NAC)
A set of instructions/ protocols that define how devices need to act on a network.
How is NAC implemented??
E.g. What questions are asked??
- What Device is it??
- What Software or Applications have been Downloaded onto the device??
- Where is the device Located??
- Who has Access to that device??
Define “Principle of Least Privilege”
A user can join a Network, but that are given very limited accessibility and actions.
Define “Mandatory Access Control”
Anyone that has joined a Network can only access data if they have appropriate clearance.
Define “Discretionary Access Control”
A user that joins a Network will need the Data Owners permission to access a specific file.
Define “Role-Based Control”
Only certain Permissions are given to a specific user/ group on a Network.
Define “Rule-Based Control”
A set of Permissions that are Condition-Specific.
E.g. Certain times of day.
Define “Data Access Control” (DAC)
After a device has joined a Network, a DAC must give the appropriate Permissions.
Define “Packet Filtering”
The firewall inspects the Packet coming into the network. If the Packet is flagged, then it is NOT authorised.
Define “Application Level”
“Application Level” controls the packets coming in and out of an application.
Define “Inbound - Outbound”
Set of rules a packet must follow when entering or exiting a network/ application.
_____ “Allow the traffic through”
Accepted
_____ “Dropped with the ‘Unreachable’ reply”
Rejected
_____ “Dropped with no reply”
Dropped
