3.3.9

Firewalls

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Firewalls

It is important to monitor and filter data coming into and out of a network.

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Firewalls

  • A firewall is either a hardware device or a piece of software which sits between a device and the Internet.
  • Firewalls inspect and filter incoming and outgoing data packets.
  • They try to stop hackers gaining access to the network and stop malware getting into the network.
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Packet filtering

  • One role of the firewall is packet filtering.
  • The firewall inspects each packet and drops those which do not meet certain criteria.
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IP-address filtering

  • The firewall only allows traffic from certain known sources.
  • This can be used to prevent denial of service attacks.
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Port-blocking

  • Firewalls can block access to certain ports.
    • One important port is port 22, which allows remote access via the Internet. By blocking this port, we can prevent hackers trying to take over the server.

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1Components of a Computer

1.1Structure & Function of the Processor

1.1.1Structure of the CPU

1.1.2Fetch, Decode, Execute Cycle

1.1.3Factors Affecting CPU Performance

1.1.4CPU Architecture

1.2Types of Processors

1.2.1CISC & RISC

1.2.2Multicore & Parallel Cores

1.3Input, Output & Storage

1.3.1Computer Systems

1.3.2Magnetic Storage

1.3.3Optical Storage

1.3.4Types of Optical Storage

1.3.5Types of Memory

1.3.6Flash Memory

1.3.7Virtual Memory

2Software & Software Development

2.1Systems Software

2.1.1Operating Systems

2.1.2Managing Memory

2.1.3Paging, Segmentation & Virtual Memory

2.1.4Device Management & Drivers

2.1.5Interrupts

2.1.6Scheduling

2.1.7Types of Operating System

2.2Applications Generation

2.2.1Applications Software & Utilities

2.2.2Encryption & Defragmentation

2.2.3Data Compression & Backup

2.2.4Open Source vs Proprietary Software

2.2.5Translators

2.2.6Compiling a Program

2.2.7Linkers, Loaders & Libraries

2.3Software Development

2.3.1Algorithmic Thinking

2.3.2Waterfall Lifecycle

2.3.3Agile Methodology

2.3.4Extreme Programming

2.3.5Spiral Methodology

2.3.6Rapid Application Development

2.4Types of Programming Language

2.4.1Types of Programming Languages

2.4.2Programming Paradigms

2.4.3Assembly & Machine Code

2.4.4Modes of Addressing Memory

2.4.5Object-Oriented Languages

2.4.6Encapsulation & Polymorphism

3Exchanging Data

3.1Compression, Encryption & Hashing

3.1.1Compression

3.1.2Encryption

3.2Databases

3.2.1Databases

3.2.2Managing Databases

3.2.3SQL

3.2.4Principles of Data Storage

3.3Networks

3.3.1Networks Introduction

3.3.2Types of Networks

3.3.3Network Protocols

3.3.4The Internet

3.3.5DNS & Web Hosting

3.3.6Layers

3.3.7Packet Switching

3.3.8Network Hardware

3.3.9Firewalls

3.3.10Proxies

3.3.11Client-Server Model

3.3.12Peer-to-Peer Model

3.4Web Technologies

3.4.1HTML

3.4.2CSS & JavaScript

3.4.3Search Engine Indexing

3.4.4Server & Client-Side Processing

4Data Types, Data Structures & Algorithms

4.1Data Types

4.1.1Data Types

4.1.2Arrays & Strings

4.1.3Representing Numbers

4.1.4Binary Arithmetic

4.1.5Hexadecimal

4.1.6Converting Binary Numbers

4.1.7Floating Points in Binary

4.1.8Floating Point Arithmetic

4.1.9Bitwise Manipulation

4.1.10Character Sets

4.2Data Structures

4.2.1Arrays, Linked Lists & Queues

4.2.2Graphs, Hash Tables & Stacks

4.2.3Trees

4.3Boolean Algebra

4.3.1Computational Logic

4.3.2Boolean Logic

4.3.3Karnaugh Maps

4.3.4Boolean Identities

4.3.5Flip Flops & Adder Circuits

5Legal, Moral, Cultural & Ethical Issues

5.1Computing Related Legislation

5.1.1Data Protection Act (1998)

5.1.2Computer Misuse Act (1990)

5.1.3Copyright Designs and Patents Act (1988)

5.1.4Regulation of Investigatory Powers Act (2000)

5.2Moral & Ethical Issues

5.2.1Online Activity Tracking

5.2.2Censorship

5.2.3Cultural Issues

5.2.4Environmental Issues

5.2.5Layout, Colour Paradigms & Character Sets

6Elements of Computational Thinking

6.1Thinking Abstractly

6.1.1Abstraction

6.2Thinking Procedurally

6.2.1Decomposition

6.3Thinking Logically

6.3.1Pseudocode & Flow Diagrams

7Problem Solving & Programming

7.1Programming Techniques

7.1.1Programming Fundamentals

7.1.2Modularity

7.2Programming Construction

7.2.1Integrated Development Environments

7.2.2Testing

8Algorithms

8.1Algorithms

8.1.1Interpreting, Correcting & Completing Algorithm

8.1.2Sort Algorithms

8.1.3Insertion & Merge Sort

8.1.4Search Algorithms

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Network Hardware

Proxies