In computing, a firewall is a software or hardware-based network security system that controls the incoming and outgoing network traffic based on applied rule set. A firewall establishes a barrier between a trusted, secure internal network and another network (e.g., the Internet) that is not assumed to be secure and trusted.
Many personal computer operating systems include software-based firewalls to protect against threats from the public Internet. Many routers that pass data between networks contain firewall components and, conversely, many firewalls can perform basic routing functions.
This document discusses cyber crime and cyber security. It begins with an introduction and overview of the history and categories of cyber crime. Some key types of cyber crime discussed include hacking, denial of service attacks, and child pornography. The document then covers advantages of cyber security like privacy policies and keeping software updated. It concludes by noting that cyber crime involves both traditional crimes and new crimes addressed by cyber law, and that cyber security is needed to help combat cyber criminals.
1. Cybercrime involves using computers or the internet to facilitate illegal activities such as identity theft, hacking, and financial fraud. The first recorded cybercrime took place in 1820.
2. Common types of cyber attacks include financial fraud, sabotage of networks or data, theft of proprietary information, unauthorized system access, and denial of service attacks. Hacking, pornography, viruses, and software piracy are also examples of cybercrimes.
3. Managing cybersecurity risks requires understanding threats like criminals and spies, vulnerabilities in systems and supply chains, and potential impacts such as data theft, service disruptions, and damage to infrastructure. Strong defenses, insider monitoring, and rapid patching are keys to risk reduction.
This document discusses web security and outlines some key terminology and issues. It defines internet security as protecting information by preventing, detecting, and responding to attacks. Some key points made are that 1 in 8 computers are infected with malware, spam and phishing attacks are common threats, and firewalls and antivirus software can help secure systems and block unwanted traffic. The document also provides definitions for common security terms like hackers, viruses, Trojan horses, and ransomware.
Virtual private networks (VPNs) allow remote access to private networks over public telecommunications networks like the Internet. VPNs use encryption, authentication, and tunneling protocols to securely connect remote users to a private network. They provide cost savings over traditional private networks by reducing equipment and maintenance costs while increasing flexibility and scalability. However, VPN performance depends on public networks and proper security deployment is required to mitigate risks.
The document discusses different types of firewalls including hardware and software firewalls, and describes their purposes and functions. It outlines the history of firewalls from their origins in the late 1980s to prevent unauthorized access. The document also defines various firewall techniques like packet filtering, application gateways, and proxy servers; and types such as stateful inspection firewalls, unified threat management firewalls, and next-generation firewalls.
An open, unencrypted wireless network can 'sniff' or capture and record the traffic, gain unauthorized access to internal network resources as well as to the internet, and then use the information and resources to perform disruptive or illegal acts.Many laptop computers have wireless cards pre-installed. The ability to enter a network while mobile has great benefits. However, wireless networking is prone to some security. Wireless networks relatively easy to break into, and even use wireless technology to hack into wired networks.The risks to users of wireless technology have increased as the service has become more popular.As a result, it is very important that enterprises define effective wireless security policies that guard against unauthorized access to important resources.
Computer Security : Introduction, Need for security, Principles of Security,
Types of Attacks
Cryptography : Plain text and Cipher Text, Substitution techniques, Caesar
Cipher, Mono-alphabetic Cipher, Polygram, Polyalphabetic Substitution,
Playfair, Hill Cipher, Transposition techniques, Encryption and Decryption,
Symmetric and Asymmetric Key Cryptography, Steganography, Key Range and
Key Size,
Possible Types of Attacks
Symmetric Key Algorithms and AES: Algorithms types and modes, Overview
of Symmetric key Cryptography, Data Encryption Standard (DES), International
Data Encryption Algorithm (IDEA), RC4, RC5, Blowfish, Advanced Encryption
Standard (AES)
Asymmetric Key Algorithms, Digital Signatures and RSA: Brief history of
Asymmetric Key Cryptography, Overview of Asymmetric Key Cryptography,
RSA algorithm, Symmetric and Asymmetric key cryptography together, Digital
Signatures, Knapsack Algorithm, Some other algorithms (Elliptic curve
cryptography, ElGamal, problems with the public key exchange)
This document discusses intrusion detection systems (IDS), beginning with historical examples of cyber attacks. It describes the role of firewalls in network security and how IDS serve as a complementary technique to firewalls by monitoring network traffic and detecting intrusions. The document outlines different types of IDS, including host-based, network-based, and hybrid systems. It also covers common intrusion detection techniques and the limitations of IDS in providing comprehensive security.
Security zones segregate networks into different areas with varying levels of security. The most secure zone contains private networks and servers, while less secure zones like DMZs contain servers accessible from untrusted networks. Device security involves physical security of network components and their locations as well as logical security measures like access control lists and authentication on routers.
A firewall can be either software-based or hardware-based, and is used to help secure a network by preventing unauthorized access. There are several types of firewalls including network layer, application layer, circuit layer, stateful multi-layer inspection, proxy, host-based, and hybrid firewalls. Firewalls work at different levels, from just packet filtering at the network level, to deep packet inspection and application-level filtering at higher levels.
A firewall is a device or software that provides secure connectivity between internal and external networks by protecting confidential information from unauthorized access, and defending the network and its resources from malicious external users and accidents. There are two main types of firewalls - hardware firewalls which are physical devices that can protect an entire network but are more expensive and complex, and software firewalls which protect individual computers and are cheaper and simpler to configure. Firewall techniques include packet filtering, application gateways, proxy servers, circuit-level gateways, and bastion hosts.
This document discusses network security and firewalls. It defines security threats as risks that can harm computer systems, and notes that network security covers technologies, devices, and processes to protect network integrity, confidentiality, and accessibility. It describes how firewalls monitor incoming and outgoing traffic to block malicious traffic, and explains the importance of network security for trust, protection from malware, and secure online transactions.
The document provides an overview of cyber security, including its importance, key domains and types. It discusses network security, application security, information security, identity management, operational security and other areas. It defines cyber security as protecting networks, devices, programs and data from threats. The document also covers cyber threats, vulnerabilities, cyber warfare, cyber terrorism and the need for critical infrastructure security. It provides examples and details for concepts like the CIA triad of confidentiality, integrity and availability.
Network security involves implementing physical and software measures to protect a network from unauthorized access and enable authorized access. It aims to maintain confidentiality of data, integrity of data, availability of resources, and privacy of personal data. Key aspects of network security include encryption to scramble data, firewalls to control access to networks, and securing wireless networks through standards like WPA2. Common security processes also involve backing up data regularly, using access controls like passwords, and encrypting data during storage and transmission.
Computer Networking: Subnetting and IP AddressingBisrat Girma
The document discusses IP addressing and subnetting. It provides an overview of classful addressing and how IP addresses were originally divided into classes A, B, and C. It then covers special addresses, private addresses, methods for identifying the class of an IP address, network addresses, subnet masks, CIDR notation, and how to calculate the number of subnets and hosts per subnet. The goal is to explain the fundamental concepts behind IP addressing and subnetting.
This document discusses cyber crime and cyber security. It begins with an introduction and overview of the history and categories of cyber crime. Some key types of cyber crime discussed include hacking, denial of service attacks, and child pornography. The document then covers advantages of cyber security like privacy policies and keeping software updated. It concludes by noting that cyber crime involves both traditional crimes and new crimes addressed by cyber law, and that cyber security is needed to help combat cyber criminals.
1. Cybercrime involves using computers or the internet to facilitate illegal activities such as identity theft, hacking, and financial fraud. The first recorded cybercrime took place in 1820.
2. Common types of cyber attacks include financial fraud, sabotage of networks or data, theft of proprietary information, unauthorized system access, and denial of service attacks. Hacking, pornography, viruses, and software piracy are also examples of cybercrimes.
3. Managing cybersecurity risks requires understanding threats like criminals and spies, vulnerabilities in systems and supply chains, and potential impacts such as data theft, service disruptions, and damage to infrastructure. Strong defenses, insider monitoring, and rapid patching are keys to risk reduction.
This document discusses web security and outlines some key terminology and issues. It defines internet security as protecting information by preventing, detecting, and responding to attacks. Some key points made are that 1 in 8 computers are infected with malware, spam and phishing attacks are common threats, and firewalls and antivirus software can help secure systems and block unwanted traffic. The document also provides definitions for common security terms like hackers, viruses, Trojan horses, and ransomware.
Virtual private networks (VPNs) allow remote access to private networks over public telecommunications networks like the Internet. VPNs use encryption, authentication, and tunneling protocols to securely connect remote users to a private network. They provide cost savings over traditional private networks by reducing equipment and maintenance costs while increasing flexibility and scalability. However, VPN performance depends on public networks and proper security deployment is required to mitigate risks.
The document discusses different types of firewalls including hardware and software firewalls, and describes their purposes and functions. It outlines the history of firewalls from their origins in the late 1980s to prevent unauthorized access. The document also defines various firewall techniques like packet filtering, application gateways, and proxy servers; and types such as stateful inspection firewalls, unified threat management firewalls, and next-generation firewalls.
An open, unencrypted wireless network can 'sniff' or capture and record the traffic, gain unauthorized access to internal network resources as well as to the internet, and then use the information and resources to perform disruptive or illegal acts.Many laptop computers have wireless cards pre-installed. The ability to enter a network while mobile has great benefits. However, wireless networking is prone to some security. Wireless networks relatively easy to break into, and even use wireless technology to hack into wired networks.The risks to users of wireless technology have increased as the service has become more popular.As a result, it is very important that enterprises define effective wireless security policies that guard against unauthorized access to important resources.
Computer Security : Introduction, Need for security, Principles of Security,
Types of Attacks
Cryptography : Plain text and Cipher Text, Substitution techniques, Caesar
Cipher, Mono-alphabetic Cipher, Polygram, Polyalphabetic Substitution,
Playfair, Hill Cipher, Transposition techniques, Encryption and Decryption,
Symmetric and Asymmetric Key Cryptography, Steganography, Key Range and
Key Size,
Possible Types of Attacks
Symmetric Key Algorithms and AES: Algorithms types and modes, Overview
of Symmetric key Cryptography, Data Encryption Standard (DES), International
Data Encryption Algorithm (IDEA), RC4, RC5, Blowfish, Advanced Encryption
Standard (AES)
Asymmetric Key Algorithms, Digital Signatures and RSA: Brief history of
Asymmetric Key Cryptography, Overview of Asymmetric Key Cryptography,
RSA algorithm, Symmetric and Asymmetric key cryptography together, Digital
Signatures, Knapsack Algorithm, Some other algorithms (Elliptic curve
cryptography, ElGamal, problems with the public key exchange)
This document discusses intrusion detection systems (IDS), beginning with historical examples of cyber attacks. It describes the role of firewalls in network security and how IDS serve as a complementary technique to firewalls by monitoring network traffic and detecting intrusions. The document outlines different types of IDS, including host-based, network-based, and hybrid systems. It also covers common intrusion detection techniques and the limitations of IDS in providing comprehensive security.
Security zones segregate networks into different areas with varying levels of security. The most secure zone contains private networks and servers, while less secure zones like DMZs contain servers accessible from untrusted networks. Device security involves physical security of network components and their locations as well as logical security measures like access control lists and authentication on routers.
A firewall can be either software-based or hardware-based, and is used to help secure a network by preventing unauthorized access. There are several types of firewalls including network layer, application layer, circuit layer, stateful multi-layer inspection, proxy, host-based, and hybrid firewalls. Firewalls work at different levels, from just packet filtering at the network level, to deep packet inspection and application-level filtering at higher levels.
A firewall is a device or software that provides secure connectivity between internal and external networks by protecting confidential information from unauthorized access, and defending the network and its resources from malicious external users and accidents. There are two main types of firewalls - hardware firewalls which are physical devices that can protect an entire network but are more expensive and complex, and software firewalls which protect individual computers and are cheaper and simpler to configure. Firewall techniques include packet filtering, application gateways, proxy servers, circuit-level gateways, and bastion hosts.
This document discusses network security and firewalls. It defines security threats as risks that can harm computer systems, and notes that network security covers technologies, devices, and processes to protect network integrity, confidentiality, and accessibility. It describes how firewalls monitor incoming and outgoing traffic to block malicious traffic, and explains the importance of network security for trust, protection from malware, and secure online transactions.
The document discusses cyber law and the Information Technology Act 2000 and its 2008 amendment in India. It provides definitions of cyber law and outlines some key areas like cyber crimes, electronic signatures, and intellectual property. It summarizes important sections of the original IT Act related to hacking, publishing sexually explicit content, and tampering with computer systems. The penalties for violations are mentioned. The amendment in 2008 added additional focus on data security, cyber terrorism and data protection. It increased the number of sections dealing with cyber-related offenses.
Intrusion detection and prevention systemNikhil Raj
This presentation describes how to implement Network based Intrusion Detection System (SNORT) in the network. Detecting and analyzing alerts generated and blocking the Attacker using Access Control List.
The document discusses a 360 degree online self-review tool called 360 degree safe that allows schools to assess and benchmark their e-safety policies and practices. The tool provides schools with summaries of their e-safety improvement, resources and guidance to support progress, and the ability to engage stakeholders. It also allows schools to benchmark against other schools and apply for an e-safety accreditation mark once minimum standards are met. The tool provides insight into e-safety practices across UK schools, finding strengths in areas like filtering and acceptable use policies but also weaknesses like community engagement, governor training, and impact measurement of e-safety programs.
Sexting all schools handout no video.pptxkathy olsson
The document discusses issues related to sexting among young people in schools, including definitions of sexting, reasons why young people engage in it, legal issues, prevalence rates, and guidance for how schools should address sexting incidents and educate students on the topic through measures such as curriculum and teaching resources. It also provides two case studies as examples of sexting situations schools may encounter and how parents can discuss sexting.
Firewalls are systems designed to prevent unauthorized access to private networks. There are several types of firewalls, including packet-filtering routers, stateful inspection firewalls, application proxies, and circuit-level gateways. Firewalls can be configured in different ways, such as using a single bastion host with a packet-filtering router, a dual-homed bastion host, or a screened subnet configuration with two routers and a bastion host subnet for the highest level of security.
This document discusses information security policies, standards, and practices. It explains the different types of security policies an organization may have, including general security policies, issue-specific policies, and system-specific policies. It emphasizes the importance of management support for security policies and outlines the key components of an information security blueprint, including management controls, operational controls, and technical controls. The document also discusses the importance of security education, training, and awareness programs to ensure all employees understand and comply with security policies and procedures.
The document discusses firewall implementation for a company called Acme. It describes how Acme can set up firewalls to restrict access between internal and external networks and between different internal departments. Packet filtering, proxy servers, and demilitarized zones are implemented to enforce access controls and monitor network traffic flow while protecting sensitive data. The completed Acme intranet design includes multiple firewalls configured in screened subnets and dual-homed gateways to secure remote access and internal information flows.
Secure by Design - Security Design Principles for the Rest of UsEoin Woods
Security is an ever more important topic for system designers. As our world becomes digital, today’s safely-hidden back office system is tomorrow’s public API, open to anyone on the Internet with a hacking tool and time on their hands. So the days of hoping that security is someone else’s problem are over.
The security community has developed a well understood set of principles used to build systems that are secure (or at least securable) by design, but this topic often isn’t included in the training of software developers, assuming that it’s only relevant to security specialists.
In this talk, we will briefly discuss why security needs to be addressed as part of architecture work and then introduce a set of proven principles for the architecture of secure systems, explaining each in the context of mainstream system design, rather than in the specialised language of security engineering.
This version of the talk was presented at GOTO London in October 2016.
The document discusses various ways that data mining can be applied for security applications such as intrusion detection, firewall policy management, worm detection, and counter-terrorism surveillance. It describes techniques like anomaly detection, link analysis, classification, and prediction that can help detect cyber attacks, trace malware authors, and predict future threats. It also addresses challenges of working with real-time streaming data from sensors for critical applications.
The document discusses four main types of firewalls: packet filtering firewalls, application proxy firewalls, stateful inspection firewalls, and circuit-level proxy firewalls. Packet filtering firewalls apply rules to IP packets to forward or discard them. Application proxy firewalls act as a relay for application-level traffic by validating and acting on requests. Stateful inspection firewalls supplement packet filtering with connection tracking. Circuit-level proxy firewalls set up two TCP connections rather than allowing direct end-to-end connections.
Look for events that are anomalous given their context, such as:
- Time of day (e.g. activity at 3am)
- Source/destination (e.g. traffic from unknown IP)
- Associated events (e.g. login without subsequent activity)
- Normal volume patterns (e.g. spike in requests)
Analyze events in context to identify deviations from normal patterns.
BASIC OF ROUTERS,ROUTER IOS AND ROUTING PROTOCOLSamiteshg
1. Routers are networking devices that connect different networks and forward data packets between them. They maintain routing tables to determine the best paths between networks.
2. The main functions of routers are packet forwarding, packet switching, and packet filtering. Routers examine packet headers to determine the best path using routing tables and switch packets between interfaces.
3. Common router operating systems are Cisco IOS and Juniper JUNOS. Cisco IOS is customized for Cisco devices and provides tools for management, memory allocation, and file storage. Juniper JUNOS offers a modular architecture and policy-based traffic controls.
The document discusses the importance of establishing a security policy for an organization. A security policy is a formal statement that outlines the organization's goals, objectives, and procedures for information security. It requires compliance, identifies consequences for non-compliance, and establishes a baseline for minimizing risk. The document outlines the key components of a security policy, including governing policies, technical policies, and guidelines. It also discusses developing a security policy through identifying issues, analyzing risks, drafting language, legal review, and deployment.
This document discusses the key components of a network design process by drawing an analogy to building design. It states that a network design consists of describing the technology, topology, products, device configurations, services, vendors, locations, and general structure. It also includes network functions like security and management. Similarly, a building design needs to understand the purpose and layout, including how occupants will move and what resources they will need. The output of both processes are blueprints. A network design specifically produces blueprints, a component plan, vendor selection, equipment choice, service provider selection, and metrics. It takes architecture and analysis products as input to evaluate and produce these design outputs and layout the network.
The document discusses firewall design principles, characteristics, and types. It describes three common firewall configurations: screened host with single-homed bastion host, screened host with dual-homed bastion host, and screened subnet. It also covers trusted systems, access control, and defending against Trojan horse attacks.
Router is a networking device that connects different networks and selects the best path to forward packets between them. It operates at the network layer of the OSI model. Cisco is the leading router manufacturer, making 70% of the market. Routers come in different sizes for different uses - access routers for small networks, distribution routers for ISPs, and core routers for backbone networks. Static routing requires manually configuring routes, while dynamic routing uses protocols to share route information between routers automatically.
A firewall is hardware or software that protects private networks and computers from unauthorized access. There are different types of firewalls including packet filtering, application-level gateways, and circuit-level gateways. Firewalls work by inspecting packets and determining whether to allow or block them based on rules. They can protect networks and devices from hackers, enforce security policies, and log internet activity while limiting exposure to threats. However, firewalls cannot protect against insider threats, new types of threats, or viruses. Firewall configurations should be tested to ensure they are properly blocking unauthorized traffic as intended.
This chapter discusses firewall planning and design. It describes common misconceptions about firewalls and explains that firewalls are dependent on an effective security policy. It outlines the types of firewall protection including packet filtering, NAT, and application proxies. It also discusses firewall hardware and software options and limitations of firewalls.
A firewall is a system or set of rules designed to permit or deny computer applications access to networks based on a set of rules. Firewalls can be implemented through software or hardware and work by examining network packets and blocking or allowing passage based on the packet's contents. There are several types of firewalls including network layer, application layer, circuit layer, and stateful multi-layer inspection firewalls. Firewalls help secure private networks from unauthorized access from other networks like the internet.
Web security involves protecting information transmitted over the internet from attacks like viruses, worms, trojans, ransomware, and keyloggers. Users can help secure themselves by using antivirus software, avoiding phishing scams, and reporting spam. Larger attacks often involve botnets, which are networks of infected computers that can overwhelm websites and services with traffic through distributed denial of service attacks.
This document discusses physical security for protecting enterprise resources including people, data, and facilities. It covers assessing threats and vulnerabilities, choosing a secure site location, designing security for the building structure and environment, implementing physical and administrative controls, and ensuring life safety measures like fire detection and suppression. Key considerations include perimeter security, access control, environmental factors, emergency procedures, and compliance with standards to help ensure security.
Data mining (lecture 1 & 2) conecpts and techniquesSaif Ullah
This document provides an overview of data mining concepts from Chapter 1 of the textbook "Data Mining: Concepts and Techniques". It discusses the motivation for data mining due to increasing data collection, defines data mining as the extraction of useful patterns from large datasets, and outlines some common applications like market analysis, risk management, and fraud detection. It also introduces the key steps in a typical data mining process including data selection, cleaning, mining, and evaluation.
A firewall is a network security system that controls incoming and outgoing network traffic based on rules. It establishes a barrier between an internal trusted network and an external untrusted network like the Internet. Firewalls exist as both software and hardware. Hardware firewalls are standalone devices that provide network-level protection, while software firewalls install on individual devices. Common firewall techniques include packet filtering, application gateways, proxy servers, and network address translation. Firewalls are customizable and can filter traffic based on IP addresses, domains, protocols, ports, and specific words. They provide security against threats like remote access, backdoors, denial of service attacks, viruses, and spam.
There are two basic types of firewalls:
1. Network layer firewalls make decisions based on source/destination addresses and ports in IP packets. They route traffic directly and are fast but can be fooled more easily.
2. Application layer firewalls use proxy servers and perform logging/auditing of all traffic passing through. They are more secure but can impact performance and transparency.
The distinction between the two types is blurring as technologies advance to incorporate aspects of both approaches. The appropriate type depends on individual network needs.
1) Firewalls act as barriers to protect networks and computers from threats on the internet. They control incoming and outgoing network traffic by analyzing data packets and determining if they should be allowed or blocked based on rules.
2) There are different types of firewalls including software-based, hardware-based, network layer, and application layer. Network layer firewalls include packet filters and circuit level filters. Application layer firewalls can understand applications and protocols.
3) Techniques used by firewalls include packet filtering, stateful packet inspection, and application proxies. Choosing a firewall depends on ensuring security of ports, monitoring systems, and not slowing performance. Users can check if their firewall is working by performing a port scan
A firewall is a network security device that controls incoming and outgoing network traffic based on a set of security rules. It protects internal networks from unauthorized external access. There are three main types of firewalls: network layer firewalls that filter traffic at the IP level, application layer firewalls that filter traffic by application, and proxy firewalls that intercept traffic and act as an intermediary. Firewalls use packet filtering, proxy services, or stateful inspection to screen traffic and enforce the security policy of an organization. They help control access between networks with different trust levels, such as between the highly trusted internal network and the less trusted internet.
A firewall is a network security device that controls incoming and outgoing network traffic based on a set of security rules. It protects internal networks from unauthorized external access. There are three main types of firewalls: network layer firewalls that filter traffic at the IP level, application layer firewalls that filter traffic by application, and proxy firewalls that intercept traffic and act as an intermediary. Firewalls use packet filtering, proxy services, or stateful inspection to screen traffic and enforce the security policy of an organization. They help control access between networks with different trust levels, such as between the highly trusted internal network and the less trusted internet.
Firewall technology emerged in the late 1980s in response to growing threats on the internet. The first generation of firewalls were packet filters that inspected packets at the network layer based on information like source/destination addresses and port numbers. The second generation introduced stateful packet inspection, which tracked the state of network connections. The third generation analyzed traffic at the application layer to better understand application protocols and detect attacks. Modern firewalls incorporate various techniques from these generations including deep packet inspection, intrusion prevention, and application-specific rules.
Watchguard Firewall overview and implemetationKaveh Khosravi
This document explains firewall technologies and intrusion detection techniques by using the combination of watchguard firewall and snort , the widely known intrusion detection system ,.
A firewall is hardware or software that filters network traffic by allowing or denying transmission based on a set of rules to protect networks from unauthorized access. There are two main types - network layer firewalls which filter at the IP address and port level, and application layer firewalls which can filter traffic from specific applications like FTP or HTTP. A DMZ (demilitarized zone) is a physical or logical sub-network exposed to an untrusted network like the internet that contains external-facing services, protected from internal networks by firewalls. Firewalls provide security benefits like restricting access to authorized users and preventing intrusions from untrusted networks.
This document provides an overview of firewalls, including what they are, how they work, types of firewalls, and their history. A firewall is a program or device that filters network traffic between the internet and an internal network based on a set of rules. There are different types, including packet filtering routers, application-level gateways, and circuit-level gateways. Firewalls aim to only allow authorized traffic according to a security policy while protecting internal systems. They provide advantages such as restricting access and hiding internal network information but can also limit some network connectivity.
A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules.
Firewalls have been the first line of defense in network security for over 25 years. They establish a barrier between secured and controlled internal networks that can be trusted and untrusted outside networks, such as the Internet.
A firewall can be hardware, software, or both.
This document provides an overview of firewalls, including what they are, different types, basic concepts, their role, advantages, and disadvantages. It defines a firewall as a program or device that filters network traffic between the internet and a private network based on a set of rules. The document discusses software vs hardware firewalls and different types like packet filtering, application-level gateways, and circuit-level gateways. It also covers the history of firewalls, their design goals, and how they concentrate security and restrict access to trusted machines only.
This document provides an overview of firewalls, including what they are, different types, basic concepts, their role, advantages, and disadvantages. It defines a firewall as a program or device that filters network traffic between the internet and a private network based on a set of rules. The document discusses software vs hardware firewalls and different types like packet filtering, application-level gateways, and circuit-level gateways. It also covers the history of firewalls, their design goals, and how they concentrate security and restrict access to trusted machines only.
Firewall technology emerged in the late 1980s and has evolved through three generations. The first generation used packet filters that inspected packets to block or allow them. The second generation added stateful inspection to track the state of connections. The third generation filters at the application layer to understand application protocols. There are different types of firewalls including network layer filters, application layer firewalls, proxies, and network address translation (NAT) which hides protected addresses.
This document discusses firewalls, including their definition, history, types, and purposes. A firewall is a program or hardware device that filters network traffic between the internet and an internal network based on a set of security rules. There are different types of firewalls, including packet filtering routers, application-level gateways, and circuit-level gateways. Firewalls aim to restrict network access and protect internal systems by only allowing authorized traffic according to a security policy.
This document provides an overview of firewalls, including what they are, their history, types, and basic concepts. A firewall is a program or hardware device that filters network traffic between the internet and an internal network or computer. There are different types, including packet filtering routers, application-level gateways, and circuit-level gateways. Firewalls aim to only allow authorized traffic according to a security policy while protecting systems from outside penetration. They provide advantages like concentrating security but also disadvantages like potentially blocking some network access.
This document discusses firewalls and their types. It begins by explaining that firewalls protect networks by guarding entry points and are becoming more sophisticated. It then defines a firewall as a network security system that controls incoming and outgoing network traffic based on rules. The document outlines different generations of firewalls and describes four main types: packet filtering, stateful packet inspection, application gateways/proxies, and circuit-level gateways. It details the characteristics, strengths, and weaknesses of each type. Finally, it emphasizes that networks are still at risk of attacks and that firewalls have become ubiquitous, so choosing the right solution depends on needs, policies, resources.
ppt consists of history, generations of firewalls, types, architectures, advantages & disadvantages.
very basic ppt- can be used for college & paper presentation seminars.
Lakshmi.S presents information on firewalls including definitions, types, and concepts. A firewall filters internet access to protect private networks. There are software and hardware firewalls. Types include packet filtering routers, application-level gateways, and circuit-level gateways. Firewalls concentrate security, filter unnecessary protocols, hide internal information, and require connections through the firewall. While firewalls improve security, they can hamper some network access and concentrating security in one location means compromising the firewall poses risks.
This document provides guidelines for setting up a forensic laboratory. It discusses the objectives, hardware and software requirements, and various aspects of laboratory design including security, plumbing, electrical systems, and universal components. The design process involves planning, design, construction, and moving phases. Considerations for laboratory setup include maximizing functions, ensuring security and non-contamination of evidence, and separating incompatible activities.
Designing and building a forensic laboratory is a complicated undertaking. Design issues include those considerations present when designing any building, with enhanced concern and special requirements involving environmental health and safety, hazardous materials, management, operational efficiency, adaptability, security of evidence, preservation of evidence in an uncontaminated state, as well as budgetary concerns.
Distributed systems
1.Write a program for implementing Client Server communication model.
2.Write a program to show the object communication using RMI.
3.Show the implementation of Remote Procedure Call.
4.Show the implementation of web services.
5.Write a program to execute any one mutual exclusion algorithm.
6.Write a program to implement any one election algorithm
7.Show the implementation of any one clock synchronization algorithm.
8.Write a program to implement two phase commit protocol
Data mining (DM) manual.
Data mining refers to the process of analysing the data from different perspectives and summarizing it into useful information.
Data mining software is one of the number of tools used for analysing data. It allows users to analyse from many different dimensions and angles, categorize it, and summarize the relationship identified.
Data mining is about technique for finding and describing Structural Patterns in data.
Embedded System, EMBEDDED SYSTEM: AN INTRODUCTION, ELEMENTS OF EMBEDDED SYSTEMS, CORE THE OF EMBEDDED SYSTEM, CHARACTERISTICS & QUALITY ATTRIBUTES OF EMBEDDED SYSTEMS, EMBEDDED HARDWARE FROM SOFTWARE PROGRAMMERS PERSPECTIVE,
Advance Database Management Systems -Object Oriented Principles In DatabaseSonali Parab
An OODBMS is the result of combining object oriented programming principles with database management principles. Object oriented programming concepts such as encapsulation, polymorphism and inheritance are enforced as well as database management concepts such as the ACID properties (Atomicity, Consistency, Isolation and Durability) which lead to system integrity, support for an ad hoc query language and secondary storage management systems which allow for managing very large amounts of data. The Object Oriented Database Manifesto specifically lists the following features as mandatory for a system to support before it can be called an OODBMS; Complex objects, Object identity, Encapsulation , Types and Classes , Class or Type Hierarchies, Overriding, overloading and late binding, Computational completeness , Extensibility,Persistence , Secondary storage management, Concurrency, Recovery and an Ad Hoc Query Facility.
Cloud and Ubiquitous Computing manual Sonali Parab
This manual consist of cloud and Ubiquitous Computing practicals of the following topics:
1.Implement Windows / Linux Cluster,
2.Developing application for Windows Azure,
3.Implementing private cloud with Xen Server,
4.Implement Hadoop,
5.Develop application using GAE,
6.Implement VMWAre ESXi Server,
7.Native Virtualization using Hyper V,
8.Using OpenNebula to manage heterogeneous distributed data center infrastructures.
Advance Database Management Systems -Object Oriented Principles In DatabaseSonali Parab
This document provides an overview of object-oriented database management systems (OODBMS), which combine object-oriented programming principles with database management. It discusses how OODBMSs support encapsulation, polymorphism, inheritance and ACID properties while allowing for complex objects, relationships, and queries of large amounts of data. The document also lists advantages and disadvantages of OODBMSs compared to relational database systems and examples of both proprietary and open-source OODBMSs.
Default and On demand routing - Advance Computer NetworksSonali Parab
Routing is the process of selecting best paths in a network. In the past, the term routing was also used to mean forwarding network traffic among networks. However this latter function is much better described as simply forwarding. Routing is performed for many kinds of networks, including the telephone network (circuit switching), electronic data networks (such as the Internet), and transportation networks.
In packet switching networks, routing directs packet forwarding (the transit of logically addressed network packets from their source toward their ultimate destination) through intermediate nodes. Intermediate nodes are typically network hardware devices such as routers, bridges, gateways, firewalls, or switches. General-purpose computers can also forward packets and perform routing, though they are not specialized hardware and may suffer from limited performance. The routing process usually directs forwarding on the basis of routing tables which maintain a record of the routes to various network destinations. Thus, constructing routing tables, which are held in the router's memory, is very important for efficient routing. Most routing algorithms use only one network path at a time. Multipath routing techniques enable the use of multiple alternative paths.
This document discusses the history and characteristics of cloud computing. It begins by defining cloud computing as relying on shared resources over a network similar to a utility. Key aspects include maximizing shared resources, dynamic reallocation of resources based on demand, and access to applications via the internet without direct installation. The document then covers the history of cloud computing from the mainframe era to modern cloud services. It describes characteristics like agility, cost reduction, scalability and elasticity. Finally, it outlines the common cloud service models of Infrastructure as a Service, Platform as a Service and Software as a Service.
The document discusses the protocol layers in Bluetooth technology. It describes that Bluetooth uses a hierarchical model with different protocol layers, each performing specific communication tasks. Some key layers mentioned are the baseband layer, link layer, host controller interface, logical link control applications protocol, RF communications protocol, and service discovery protocol. The document provides details on the functions of different Bluetooth protocol layers like the baseband layer managing the radio interface and link management protocol handling link setup between devices.
Protocol layers are a hierarchical model of network or communication functions. The divisions of the hierarchy are referred to as layers or levels, with each layer performing a specific task. In addition, each protocol layer obtains services from the protocol layer below it and performs services for the protocol layer above it. The Bluetooth system divides communication functions into protocol layers.
The Bluetooth system consists of many existing protocols that are directly used or have been adapted to the specific use of the Bluetooth system. Protocols are often divided into groups that are used for different levels of communication (a protocol stack). Lower level protocols (such as protocols that are used to manage a radio link between specific points) are only used to create, manage, and disconnect transmission between specific points. Mid-level protocols (such as transmission control protocols) are used to create, manage, and disconnect a logical connection between endpoints that may have multiple link connections between them. High level protocols (application layer protocols) are used to launch, control, and close end-user applications.
Some of the layers associated with the Bluetooth system include the baseband layer (physical layer), link layer, host controller interface (HCI), logical link control applications protocol (L2CAP), RF Communications protocol (RFCOMM), Object Exchange (OBEX), and service discovery.
A set of computers and computer network resources based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet .
Public cloud services may be free or offered on a pay-per-usage model.
Applications, storage, and other resources are made available to the general public by a service provider. There are service providers like Amazon, Microsoft or Google who own all infrastructure at their data center.
A set of computers and computer network resources based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet .
Public cloud services may be free or offered on a pay-per-usage model.
Applications, storage, and other resources are made available to the general public by a service provider. There are service providers like Amazon, Microsoft or Google who own all infrastructure at their data center.
Data mining refers to the process of analysing the data from different perspectives and summarizing it into useful information.
Data mining software is one of the number of tools used for analysing data. It allows users to analyse from many different dimensions and angles, categorize it, and summarize the relationship identified.
Data mining is about technique for finding and describing Structural Patterns in data.
Data mining is the process of finding correlation or patterns among fields in large relational databases.
The process of extracting valid, previously unknown, comprehensible , and actionable information from large databases and using it to make crucial business decisions.
Remote Method Invocation (RMI) allows objects running in one Java virtual machine to invoke methods on objects running in another Java virtual machine. RMI uses object serialization to marshal and unmarshal parameters and supports true object-oriented polymorphism. RMI is implemented using three layers - stub, remote reference, and transport connection layers. The stub and skeleton hide the underlying network implementation details and allow remote objects to be called similar to local objects. Security is an important consideration in RMI and a security manager must be installed and permissions configured to control access to remote objects and classes.
“Software Testing is the process of executing a program or system with the intent of finding errors. Or, it involves any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results”
Currently Agile is one of the highly practiced methodologies. Agile is an evolutionary approach to software development which is performed in a highly collaborative manner by self-organizing teams that produces high quality software in a cost effective and timely way which also meets the changing needs of its stakeholders. The software is delivered to the customer very quickly; customer checks it for errors and sends some new changes and requirements to include before the last iteration. So, user is provided with a chance to test the product and provide the team with feedback about the working and the functionality of the system. Agile development approach believes in the involvement and frequent communication between the developer team and stakeholders, and regular delivery of functionality. According to Agile development, people are more important than processes and tools; and the customer must be involved in the entire process.
Data mining refers to analyzing data from different perspectives to extract useful information. There are various types of data mining including business, scientific, and internet data mining. Web mining is a main application of data mining that involves the automated discovery of useful information from web documents and services. It has three domains: web content mining which extracts patterns from online information, web structure mining which describes how content is organized, and web usage mining which analyzes web access logs to understand user behavior. Common web mining techniques include clustering, classification, association rules, path analysis, and sequential patterns. Web mining tools like Mozenda can routinely extract, store, and publish web data to be used in various applications.
Recently The Java Remote Method Invocation (RMI) system allows an object running in one Java virtual machine to invoke methods on an object running in another Java virtual machine. RMI provides for remote communication between programs written in the Java programming language.
How to Configure Time Off Types in Odoo 17Celine George
Now we can take look into how to configure time off types in odoo 17 through this slide. Time-off types are used to grant or request different types of leave. Only then the authorities will have a clear view or a clear understanding of what kind of leave the employee is taking.
The Jewish Trinity : Sabbath,Shekinah and Sanctuary 4.pdfJackieSparrow3
we may assume that God created the cosmos to be his great temple, in which he rested after his creative work. Nevertheless, his special revelatory presence did not fill the entire earth yet, since it was his intention that his human vice-regent, whom he installed in the garden sanctuary, would extend worldwide the boundaries of that sanctuary and of God’s presence. Adam, of course, disobeyed this mandate, so that humanity no longer enjoyed God’s presence in the little localized garden. Consequently, the entire earth became infected with sin and idolatry in a way it had not been previously before the fall, while yet in its still imperfect newly created state. Therefore, the various expressions about God being unable to inhabit earthly structures are best understood, at least in part, by realizing that the old order and sanctuary have been tainted with sin and must be cleansed and recreated before God’s Shekinah presence, formerly limited to heaven and the holy of holies, can dwell universally throughout creation
Lecture_Notes_Unit4_Chapter_8_9_10_RDBMS for the students affiliated by alaga...Murugan Solaiyappan
Title: Relational Database Management System Concepts(RDBMS)
Description:
Welcome to the comprehensive guide on Relational Database Management System (RDBMS) concepts, tailored for final year B.Sc. Computer Science students affiliated with Alagappa University. This document covers fundamental principles and advanced topics in RDBMS, offering a structured approach to understanding databases in the context of modern computing. PDF content is prepared from the text book Learn Oracle 8I by JOSE A RAMALHO.
Key Topics Covered:
Main Topic : DATA INTEGRITY, CREATING AND MAINTAINING A TABLE AND INDEX
Sub-Topic :
Data Integrity,Types of Integrity, Integrity Constraints, Primary Key, Foreign key, unique key, self referential integrity,
creating and maintain a table, Modifying a table, alter a table, Deleting a table
Create an Index, Alter Index, Drop Index, Function based index, obtaining information about index, Difference between ROWID and ROWNUM
Target Audience:
Final year B.Sc. Computer Science students at Alagappa University seeking a solid foundation in RDBMS principles for academic and practical applications.
About the Author:
Dr. S. Murugan is Associate Professor at Alagappa Government Arts College, Karaikudi. With 23 years of teaching experience in the field of Computer Science, Dr. S. Murugan has a passion for simplifying complex concepts in database management.
Disclaimer:
This document is intended for educational purposes only. The content presented here reflects the author’s understanding in the field of RDBMS as of 2024.
Feedback and Contact Information:
Your feedback is valuable! For any queries or suggestions, please contact muruganjit@agacollege.in
Is Email Marketing Really Effective In 2024?Rakesh Jalan
Slide 1
Is Email Marketing Really Effective in 2024?
Yes, Email Marketing is still a great method for direct marketing.
Slide 2
In this article we will cover:
- What is Email Marketing?
- Pros and cons of Email Marketing.
- Tools available for Email Marketing.
- Ways to make Email Marketing effective.
Slide 3
What Is Email Marketing?
Using email to contact customers is called Email Marketing. It's a quiet and effective communication method. Mastering it can significantly boost business. In digital marketing, two long-term assets are your website and your email list. Social media apps may change, but your website and email list remain constant.
Slide 4
Types of Email Marketing:
1. Welcome Emails
2. Information Emails
3. Transactional Emails
4. Newsletter Emails
5. Lead Nurturing Emails
6. Sponsorship Emails
7. Sales Letter Emails
8. Re-Engagement Emails
9. Brand Story Emails
10. Review Request Emails
Slide 5
Advantages Of Email Marketing
1. Cost-Effective: Cheaper than other methods.
2. Easy: Simple to learn and use.
3. Targeted Audience: Reach your exact audience.
4. Detailed Messages: Convey clear, detailed messages.
5. Non-Disturbing: Less intrusive than social media.
6. Non-Irritating: Customers are less likely to get annoyed.
7. Long Format: Use detailed text, photos, and videos.
8. Easy to Unsubscribe: Customers can easily opt out.
9. Easy Tracking: Track delivery, open rates, and clicks.
10. Professional: Seen as more professional; customers read carefully.
Slide 6
Disadvantages Of Email Marketing:
1. Irrelevant Emails: Costs can rise with irrelevant emails.
2. Poor Content: Boring emails can lead to disengagement.
3. Easy Unsubscribe: Customers can easily leave your list.
Slide 7
Email Marketing Tools
Choosing a good tool involves considering:
1. Deliverability: Email delivery rate.
2. Inbox Placement: Reaching inbox, not spam or promotions.
3. Ease of Use: Simplicity of use.
4. Cost: Affordability.
5. List Maintenance: Keeping the list clean.
6. Features: Regular features like Broadcast and Sequence.
7. Automation: Better with automation.
Slide 8
Top 5 Email Marketing Tools:
1. ConvertKit
2. Get Response
3. Mailchimp
4. Active Campaign
5. Aweber
Slide 9
Email Marketing Strategy
To get good results, consider:
1. Build your own list.
2. Never buy leads.
3. Respect your customers.
4. Always provide value.
5. Don’t email just to sell.
6. Write heartfelt emails.
7. Stick to a schedule.
8. Use photos and videos.
9. Segment your list.
10. Personalize emails.
11. Ensure mobile-friendliness.
12. Optimize timing.
13. Keep designs clean.
14. Remove cold leads.
Slide 10
Uses of Email Marketing:
1. Affiliate Marketing
2. Blogging
3. Customer Relationship Management (CRM)
4. Newsletter Circulation
5. Transaction Notifications
6. Information Dissemination
7. Gathering Feedback
8. Selling Courses
9. Selling Products/Services
Read Full Article:
https://digitalsamaaj.com/is-email-marketing-effective-in-2024/
Front Desk Management in the Odoo 17 ERPCeline George
Front desk officers are responsible for taking care of guests and customers. Their work mainly involves interacting with customers and business partners, either in person or through phone calls.
How to Handle the Separate Discount Account on Invoice in Odoo 17Celine George
In Odoo, separate discount account can be set up to accurately track and manage discounts applied on various transaction and ensure precise financial reporting and analysis
No, it's not a robot: prompt writing for investigative journalismPaul Bradshaw
How to use generative AI tools like ChatGPT and Gemini to generate story ideas for investigations, identify potential sources, and help with coding and writing.
A talk from the Centre for Investigative Journalism Summer School, July 2024
How to Show Sample Data in Tree and Kanban View in Odoo 17Celine George
In Odoo 17, sample data serves as a valuable resource for users seeking to familiarize themselves with the functionalities and capabilities of the software prior to integrating their own information. In this slide we are going to discuss about how to show sample data to a tree view and a kanban view.
How to Install Theme in the Odoo 17 ERPCeline George
With Odoo, we can select from a wide selection of attractive themes. Many excellent ones are free to use, while some require payment. Putting an Odoo theme in the Odoo module directory on our server, downloading the theme, and then installing it is a simple process.
The membership Module in the Odoo 17 ERPCeline George
Some business organizations give membership to their customers to ensure the long term relationship with those customers. If the customer is a member of the business then they get special offers and other benefits. The membership module in odoo 17 is helpful to manage everything related to the membership of multiple customers.
Join educators from the US and worldwide at this year’s conference, themed “Strategies for Proficiency & Acquisition,” to learn from top experts in world language teaching.
2. Ethical Hacking: Firewall.
1
Firewall
Objective
A firewall is a system designed to prevent unauthorized access to or from a private network.
Firewalls are frequently used to prevent unauthorized Internet users from accessing private
networks connected to the Internet, especially intranets. All messages entering or leaving the
intranet pass through the firewall, which examines each message and blocks those that do not
meet the specified security criteria.
Abstract
In computing, a firewall is a software or hardware-based network security system that
controls the incoming and outgoing network traffic based on applied rule set. A firewall
establishes a barrier between a trusted, secure internal network and another network (e.g., the
Internet) that is not assumed to be secure and trusted.
Many personal computer operating systems include software-based firewalls to protect
against threats from the public Internet. Many routers that pass data between networks
contain firewall components and, conversely, many firewalls can perform basic routing
functions.
Figure 1: Illustration of Firewall.
3. Ethical Hacking: Firewall.
2
Introduction
What is a Firewall?
A firewall is a secure Internet gateway that is used to interconnect a private network to the
Internet (see Figure 1). There are a number of components that make up a firewall:
i) The Internet access security policy of the organisation. This states, at a high level, what
degree of security the organisation expects when connecting to the Internet. The
security policy is independent of technology and techniques, and should have a lifetime
independent of the equipment used. An example of statements from such a security
policy might be: external users will not be allowed to access the corporate network
without a strong level of authentication; any corporate information not in the public
domain must be transferred across the Internet in a confidential manner, and
corporate users will only be allowed to send electronic mail to the Internet - all other
services will be banned.
ii) The mapping of the security policy onto technical designs and procedures that are
to be followed when connecting to the Internet. This information will be updated as
new technology is announced, and as system configurations change etc. For
example, regarding authentication, the technical design might specify the use of one-time
passwords. Technical designs are usually based on one of two security policies,
permit any service unless it is expressly denied, or deny any service unless it is expressly
permitted. The latter is clearly the more secure of the two.
iii) The firewall system, which is the hardware and software which implements the
firewall. Typical firewall systems comprise a IP packet filtering router, and a host
computer (sometimes called a bastion host or application gateway) running application
filtering and authentication software.
Why Firewalls?
Prevent denial of service attacks: SYN flooding: attacker establishes many bogus TCP
connections, no resources left for “real” connections.
Prevent illegal modification/access of internal data. e.g., attacker replaces CIA’s
homepage with something else.
Allow only authorized access to inside network (set of authenticated users/hosts).
There are three types of fire walls.
Packet Filter: IP Packet Filter Firewall is a firewall deciding to forward or to drop a certain
packet according to the information of the packet’s head. Packet filters act by inspecting the
"packets" which transfer between computers on the Internet. If a packet matches the packet
filter's set of rules, the packet filter will drop (silently discard) the packet, or reject it (discard
it, and send "error responses" to the source).
This type of packet filtering pays no attention to whether a packet is part of an existing
stream of traffic (i.e. it stores no information on connection "state"). Instead, it filters each
packet based only on information contained in the packet itself.
4. Ethical Hacking: Firewall.
Packet filtering firewalls work mainly on the first three layers of the OSI reference model,
which means most of the work is done between the network and physical layers, with a little
bit of peeking into the transport layer to figure out source and destination port numbers.
3
Figure 2: Packet Filtering Firewall.
Stateful Filters
Stateful filters introduce a technology of stateful inspection packet filtering. These firewalls
perform the work of their first-generation predecessors but operate up to layer 4 (transport
layer) of the OSI model. This is achieved by retaining packets until enough are available to
make a judgment about its state. Known as stateful packet inspection, it records all
connections passing through it and determines whether a packet is the start of a new
connection, a part of an existing connection, or not part of any connection. Though static
rules are still used, these rules can now contain connection state as one of their test criteria.
Certain DoS attacks bombard the firewall with thousands of fake connection packets to
overwhelm it by filling its connection state memory.
Figure 3: Stateful Inspection Firewall.
5. Ethical Hacking: Firewall.
Application Layer
Application layer filtering can "understand" certain applications and protocols (such as File
Transfer Protocol (FTP), Domain Name System (DNS), or Hypertext Transfer Protocol
(HTTP)). This is useful as it is able to detect if an unwanted protocol is attempting to bypass
the firewall on an allowed port, or detect if a protocol is being abused in any harmful way.
The existing deep packet inspection functionality of modern firewalls can be shared by
Intrusion prevention systems (IPS).
4
Figure 4: Application level gateway Firewall.
Bastion Host Firewall:
A Bastion host is a special purpose computer on a network specifically designed and
configured to withstand attacks. A firewall at layer 5 Internet (7 ISO) is sometimes called a
bastion host, application gateway, proxy server or guardian system. Its purpose is to filter
the service provided by the application. The computer generally hosts a single application,
for example a proxy server, and all other services are removed or limited to reduce the threat
to the computer. It is hardened in this manner primarily due to its location and purpose,
which is either on the outside of the firewall or in the DMZ and usually involves access from
untrusted networks or computers.
Figure 5: Bastion Host Firewall.
6. Ethical Hacking: Firewall.
5
Literature Review
The term firewall originally referred to a wall intended to confine a fire or potential fire
within a building. Later uses refer to similar structures, such as the metal sheet separating the
engine compartment of a vehicle or aircraft from the passenger compartment.
Firewall technology emerged in the late 1980s when the Internet was a fairly new technology
in terms of its global use and connectivity. The predecessors to firewalls for network security
were the routers used in the late 1980s
Clifford Stoll's discovery of German spies tampering with his system
Bill Cheswick's "Evening with Berferd" 1992 in which he set up a simple electronic "jail"
to observe an attacker
In 1988, an employee at the NASA Ames Research Center in California sent a memo
by email to his colleagues that read, "We are currently under attack from an Internet
VIRUS! It has hit Berkeley, UC San Diego, Lawrence Livermore, Stanford, and NASA
Ames."
The Morris Worm spread itself through multiple vulnerabilities in the machines of the
time. Although it was not malicious in intent, the Morris Worm was the first large scale
attack on Internet security; the online community was neither expecting an attack nor
prepared to deal with one.
First generation: Packet filters
The first paper published on firewall technology was in 1988, when engineers from Digital
Equipment Corporation (DEC) developed filter systems known as packet filter firewalls. This
fairly basic system was the first generation of what is now a highly involved and technical
internet security feature. At AT&T Bell Labs, Bill Cheswick and Steve Bellovin were
continuing their research in packet filtering and developed a working model for their own
company based on their original first generation architecture.
Packet filters act by inspecting the "packets" which are transferred between computers on the
Internet. If a packet matches the packet filter's set of filtering rules, the packet filter will drop
(silently discard) the packet or reject it (discard it, and send "error responses" to the source).
This type of packet filtering pays no attention to whether a packet is part of an existing
stream of traffic (i.e. it stores no information on connection "state"). Instead, it filters each
packet based only on information contained in the packet itself (most commonly using a
combination of the packet's source and destination address, its protocol, and, for TCP and
UDP traffic, the port number).
TCP and UDP protocols constitute most communication over the Internet, and because TCP
and UDP traffic by convention uses well known ports for particular types of traffic, a
"stateless" packet filter can distinguish between, and thus control, those types of traffic (such
7. Ethical Hacking: Firewall.
as web browsing, remote printing, email transmission, file transfer), unless the machines on
each side of the packet filter are both using the same non-standard ports.
Packet filtering firewalls work mainly on the first three layers of the OSI reference model,
which means most of the work is done between the network and physical layers, with a little
bit of peeking into the transport layer to figure out source and destination port numbers.
When a packet originates from the sender and filters through a firewall, the device checks for
matches to any of the packet filtering rules that are configured in the firewall and drops or
rejects the packet accordingly. When the packet passes through the firewall, it filters the
packet on a protocol/port number basis (GSS). For example, if a rule in the firewall exists to
block telnet access, then the firewall will block the TCP protocol for port number 23.
6
Second generation: "Stateful" filters
From 1989–1990 three colleagues from AT&T Bell Laboratories, Dave Presetto, Janardan
Sharma, and Kshitij Nigam, developed the second generation of firewalls, calling
themCircuit- level gateways.
Second-generation firewalls perform the work of their first-generation predecessors but
operate up to layer 4 (transport layer) of the OSI model. This is achieved by retaining packets
until enough information is available to make a judgement about its state. Known as stateful
packet inspection, it records all connections passing through it and determines whether a
packet is the start of a new connection, a part of an existing connection, or not part of any
connection. Though static rules are still used, these rules can now contain connection state as
one of their test criteria. Certain denial-of-service attacks bombard the firewall with
thousands of fake connection packets in an attempt to overwhelm it by filling its connection
state memory.
Third generation: application layer
Marcus Ranum, Wei Xu, and Peter Churchyard developed an Application Firewall known as
Firewall Toolkit (FWTK). In June 1994, Wei Xu extended the FWTK with the Kernel
enhancement of IP filter and socket transparent. This was known as the first transparent
Application firewall, released as a commercial product of Gauntlet firewall at Trusted
Information Systems. Gauntlet firewall was rated one of the number 1 firewalls during 1995–
1998.
The key benefit of application layer filtering is that it can "understand" certain applications
and protocols (such as File Transfer Protocol (FTP), Domain Name System (DNS),
orHypertext Transfer Protocol (HTTP)). This is useful as it is able to detect if an unwanted
protocol is attempting to bypass the firewall on an allowed port, or detect if a protocol is
being abused in any harmful way. As of 2012, the so-called next-generation firewall (NGFW)
is nothing more than the "widen" or "deepen" inspection at application-stack. For example,
8. Ethical Hacking: Firewall.
the existing deep packet inspection functionality of modern firewalls can be extended to
include i) Intrusion prevention systems (IPS);
ii) User identity integration (by binding user IDs to IP or MAC addresses for
7
"reputation"); and/or
iii) Web Application Firewall (WAF). WAF attacks may be implemented in the tool
"WAF Fingerprinting utilizing timing side channels" (WAFFle).
Study
Penetration of Firewall
Attacking Packet Filtering Firewall
• IP Address Spoofing Attack
• Denial-of-service Attack
• Tiny Fragment Attack
• Trojan Attack
Attacking Stateful Inspection Firewall
• Protocol Tunneling
• Trojans Rebound
Attacking Proxy
• Unauthorized Web Access
• Unauthorized Socks Access
• Unauthorized Telnet Access
Penetration of Firewall using WinGate.
WinGate is Integrated Gateway Management Software for Microsoft Windows,
providing web caching, firewall and NAT services, along with a number of integrated proxy
servers and also email services (SMTP, POP3 and IMAP servers).
WinGate 1.0 was first released on 5 October 1995, and was a re-write of a product that had
been previously released in prototype form by Adrien de Croy under the name SocketSet
earlier that year.
WinGate proved very popular, and by the mid to late 1990s, WinGate was almost ubiquitous
in homes and small businesses that needed to share a single Internet connection between
multiple networked computers. The introduction of Internet Connection Sharing inWindows
98 however, combined with increasing availability of cheap NAT-enabled routers, forced
WinGate to evolve to provide more than just internet connection sharing features. Today,
focus for WinGate is primarily access control, email server, caching, reporting, bandwidth
management and content filtering.
WinGate comes in three versions, Standard, Professional and Enterprise. The Enterprise
edition also provides an easily configuredvirtual private network system, which is also
available separately as WinGate VPN. Licensing is based on the number of concurrently
9. Ethical Hacking: Firewall.
connected users, and a range of license sizes are available. Multiple licenses can also be
aggregated.
8
The current version of WinGate is version 8.0.5 (released 5 December 2013).
Figure 6: WinGate.
Hardware Firewall vs Software Firewall
• Hardware firewalls are specifically built within hardware devices like routers whereas
software firewalls are software programs installed on computers.
• Hardware firewalls protect a whole network while software firewalls protect individual
computers on which they are installed.
• By default, hardware firewalls filter web packets while software firewalls may not filter
web packets unless web traffic filtering controls are enabled.
• A hardware firewall can be configured to use a proxy service for filtering packets while a
software firewall does not use a proxy service to filter.
10. Ethical Hacking: Firewall.
Firewall Analysis
Understanding the deployed firewall policy can be a daunting task. Administrators today
have no easy way of answering questions such as can I telnet from here to there? Or from
which machines can our DMZ be reached, and with which services? , or what will be the
effect of adding this rule to the firewall?' ' . These are basic questions that administrators need
to answer regularly in order to perform their jobs, and sometimes more importantly, in order
to explain the pol icy and its consequences to their management. There are several reasons
why this task is difficult, including:
1. Firewall configuration languages tend to be arcane, very low level, and highly vendor
9
specific.
2. Vendor-supplied GUIs require their users to cl ick through several windows in order
to fully understand even a single rule: at a minimum, the user needs to check the I P
addresses of the source and destination fields, and the protocols and ports underlying
the service field.
3. Firewall rule-bases are sensitive to rule order. Several rules may match a particular
packet, and usual ly the first matching rule is applied -- so changing the rule order, or
inserting a correct rule in the wrong place, may lead to unexpected behavior and
possible security breaches.
4. Alternating PASS and DROP rules create rule-bases that have complex interactions
between different rules. What pol icy such a rule-base is enforcing is hard for humans
to comprehend when there are more than a handful of rules.
Firewall Policies:
To protect private networks and individual machines from the dangers of the greater Internet,
a firewall can be employed to filter incoming or outgoing traffic based on a predefined set of
rules called firewall policies.
Policy Actions:
• Packets flowing through a firewall can have one of three outcomes:
– Accepted: permitted through the firewall
– Dropped: not allowed through with no indication of failure
– Rejected: not allowed through, accompanied by an attempt to inform the source that
the packet was rejected.
Blacklists and White Lists:
There are two fundamental approaches to creating firewall policies (or rulesets) to
effectively minimize vulnerability to the outside world while maintaining the desired
functionality for the machines in the trusted internal network (or individual computer).
11. Ethical Hacking: Firewall.
10
• Blacklist approach
– All packets are allowed through except those that fit the rules defined specifically in a
blacklist. This type of configuration is more flexible in ensuring that service to the
internal network is not disrupted by the firewall.
Figure 7: Black list firewall approach.
• Whitelist approach
– A safer approach to defining a firewall ruleset is the default-deny policy, in which
packets are dropped or rejected unless they are specifically allowed by the firewall
Figure 8: White list firewall approach
12. Ethical Hacking: Firewall.
11
Methodology
Design Principles of Firewall
i. Packet Filtering Firewall:
Allow the packet which match the established rule set to pass and deny the packet which
violate the established rule set, at the same time, it will record log message, alarm the
administrator when a policy has been violated.
Working of Packet Filtering Firewall.
• A packet filter has a set of rules with accept or deny actions
• Based on the information contained in the packet itself
• Using different field in the head of the packet to filter, include the packet's source and
destination address, its protocol, port number, and so on
• When the packet filter receives a packet of information, the filter compares the packet to
your pre-configured rule set
• At the first match, the packet filter either accepts or denies the packet of information
Figure 9: Working of Packet Filtering Firewall.
13. Ethical Hacking: Firewall.
A packet filtering router should be able to filter IP packets and decision to forward/drop
packets based on the following four fields:
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source IP address, destination IP address
TCP/UDP source and destination port numbers
ICMP message type
TCP SYN and ACK bits
Filtering is used to:
block connections from specific hosts or networks
block connections to specific hosts or networks
block connections to specific ports
block connections from specific ports
Example 1: block incoming and outgoing datagrams with IP protocol field = 17and with
either source or dest port = 23.
All incoming and outgoing UDP flows and telnet connections are blocked.
Example 2: Block inbound TCP segments with ACK=0.
Prevents external clients from making TCP connections with internal clients, but allows
internal clients to connect to outside.
Advantages
• High speed
• Transparent for the users
Disadvantages
• Cannot filter the packet according the containing of the packet
• Only offer brief log messages
• Every port that may be used must be open to the external network, which increase the risk
of attack
• Very difficult to configure ACL (Access Control List).
14. Ethical Hacking: Firewall.
13
ii. Stateful Inspection Firewall:
A stateful inspection firewall is a firewall that monitors the state of the connection and
compiles the information in a state table.
Working of Stateful Inspection Firewall
Stateful packet inspection (SPI) or stateful inspection is a firewall that keeps track of the state
of network connections (such as TCP streams, UDP communication) traveling across it. The
firewall is programmed to distinguish legitimate packets for different types of connections.
Only packets matching a known active connection will be allowed by the firewall; others will
be rejected.
Figure 10: Working of Stateful Inspection Firewall.
Advantages
• Safer than static packet filtering
• Better performance than static packet filtering
Disadvantages
• Security is not high enough due to fewer checks on packet data
• More detections demand higher performance of the firewall
15. Ethical Hacking: Firewall.
iii. Application Layer Gateway (ALG, or Proxy Server)
Responsible for the communication between external network and internal network. When
the users intend to communicate, they do not communicate directly, proxy will help
forwarding instead.
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Working of Application Layer Gateway (ALG, or Proxy Server)
Figure 11: Working of ALG Firewall.
Function Offered by Proxy
• Authentication mechanism
• Content Filtering
• Mature Log
Advantages
• Accelerate the network by its Cache
• Prevent any detection to internal network
• Filtering the content of the packet effectively
• Reduce direct attack to internal network
• No IP Address Spoofing Attack
• Mature Log
Disadvantages
• A special service must have a special proxy
• Too much access delay when proxy server is busy
• Opaque (not transparent) for the users
• Slower than Packet Filtering firewall
16. Ethical Hacking: Firewall.
iv. Bastion Host Firewall.
A Bastion host is a special purpose computer on a network specifically designed and
configured to withstand attacks. The computer generally hosts a single application, for
example a proxy server, and all other services are removed or limited to reduce the threat to
the computer. It is hardened in this manner primarily due to its location and purpose, which is
either on the outside of the firewall or in the DMZ and usually involves access from untrusted
networks or computers.
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Figure 12: Working of Bastion host Firewall.
Placement of Bastion hosts
There are two common network configurations that include bastion hosts and their
placement. The first requires two firewalls, with bastion hosts sitting between the first
"outside world" firewall, and an inside firewall, in a demilitarized zone (DMZ). Often smaller
networks do not have multiple firewalls, so if only one firewall exists in a network, bastion
hosts are commonly placed outside the firewall
Bastion hosts are related to multi-homed hosts and screened hosts. While a dual-homed host
often contains a firewall it is also used to host other services as well. A screened host is a
dual-homed host that is dedicated to running the firewall.
Figure 13: Internal Bastion host. Figure 14: External Bastion host.
17. Ethical Hacking: Firewall.
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Firewall Configurations
i. The Dual Homed Gateway
This is a secure firewall design comprising an application gateway and a packet filtering
router. It is called “dual homed” because the gateway has two network interfaces, one
attached to the Internet, the other to the organisation's network. Only applications with proxy
services on the application gateway are able to operate through the firewall. Since IP
forwarding is disabled in the host, IP packets must be directed to one of the proxy servers on
the host, or be rejected. Some manufacturers build the packet filtering capability and the
application proxies into one box, thereby simplifying the design (but removing the possibility
of having an optional info server and modems attached to the screened subnet, see Figure 10).
The disadvantages of the dual homed gateway are that it may be a bottleneck to performance,
and it may be too secure for some sites (!) since it is not possible to let trusted applications
bypass the firewall and communicate directly with peers on the Internet. They must have a
proxy service in the firewall.
Figure 15: Dual Homed Gateway Firewall.
ii. The Screened Host Gateway
The screened host gateway is similar to the above, but more flexible and less secure, since
trusted traffic may pass directly from the Internet into the private network, thereby bypassing
the application gateway. In this design the application gateway only needs a single network
connection
The IP router will normally be configured to pass Internet traffic to the application gateway
or to reject it. Traffic from the corporate network to the Internet will also be rejected, unless
it originates from the application gateway. The only exception to these rules will be for
trusted traffic that will be allowed straight through.
Figure 16: The screened host gateway Firewall.
18. Ethical Hacking: Firewall.
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iii. The Screened Subnet Gateway
This configuration creates a small isolated network between the Internet and the corporate
network, which is sometimes referred to as the demilitarised zone (DMZ), see Figure 12. The
advantages of this configuration is that multiple hosts and gateways can be stationed in the
DMZ, thereby achieving a much greater throughput to the Internet than the other
configurations; plus the configuration is very secure as two packet filtering routers are there
to protect the corporate network.
The IP router on the Internet side will only let through Internet traffic that is destined for a
host in the DMZ (and vice versa). The IP router on the corporate network side will only let
site traffic pass to a host in the DMZ (and vice versa).
This system is as secure as the dual homed gateway, but it is also possible to allow trusted
traffic to pass straight through the DMZ if required. This configuration is of course more
expensive to implement!
Figure 17: The Screened Subnet Gateway Firewall.
iv. Double Proxying and a DMZ
The configuration shown in Figure 13 is even more secure that the screened subnet seen in
the previous section. It is used by a bank to protect its internal network from direct access
from the Internet. Users from the Internet have to pass through two application proxies
before they can access the bank’s intranet.
This shows that there really is no limit to how complex a firewall configuration can be. The
only limitations are the cost and performance implications of building ulta-secure firewall
configurations.
Figure 18: Double Proxying and a DMZ Firewall.
19. Ethical Hacking: Firewall.
Reviews
In short, firewalls are necessary. Without a firewall, your internet-connected PC would not
last for many minutes before succumbing to an attack. Ever since Vista, Windows operating
systems have included an excellent two-way firewall, which means it can protect against
things trying to attack from the outside and things trying to connect with their senders once
they make it inside the firewall to your computer. Many people are content to run the
Windows firewall, and there is nothing wrong with that. However, some people prefer a
firewall from the same publisher who sells their security software.
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Figure 17: The firewall.
20. Ethical Hacking: Firewall.
19
Conclusions
What Can a Firewall Do:
• Packet Inspection
• Connections and State
• Stateful Packet Inspection
• protect internal host from the risk of direct interaction
• Insulate the protected host from threats by ensuring that an external host can never directly
communicate with the protected host
Protect resources
• To protect resources from threat
• Protected resources should always be kept patched and up-to-date
• Record all communications especially access policy violations
• Through system log or proprietary logging format
• Alarm when a policy has been violated
References
1. Network Firewall Technologies-i. David W Chadwick
IS Institute, University of Salford, Salford, M5 4WT, England.
2. Packet Filtering and Stateful Firewalls
Avishai Wool, Ph.D., School of Electrical Engineering.
3. KAIST, Dept. of EECS.
4. http://en.wikipedia.org/wiki/Firewall_(computing)
5. http://my.ss.sysu.edu.cn/WebSec/download/chap6.pdf
6. http://en.wikipedia.org/wiki/WinGate