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.
This document discusses the development of a novel pattern detection processor using an adaptively divisible dual-port BiTCAM (binary ternary content-addressable memory) to achieve high-throughput, low-power and low-cost pattern detection for mobile devices. The proposed dual-port BiTCAM architecture uses a dual-port AND-type match-line scheme with dual-port active AND gates. This allows for shared storage spaces to reduce power consumption through improved storage efficiency. The divisible BiTCAM also provides flexibility to regularly update the virus database.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IRJET - Implementation of Firewall in a Cooperate Environment
This document discusses the implementation of firewalls in a corporate environment. It begins with an introduction to computer security and firewalls. Firewalls regulate information flow between computer networks and protect networks by standing between the network and outside world. There are different types of firewalls such as packet filtering, stateful, circuit level gateway, and application proxy firewalls. The document then discusses the need for firewalls in corporate environments and existing firewall systems using IPv4 and IPv6. It proposes a new firewall system based on VLANs which uses virtual LANs to allow authorized groups of computers on the network while restricting unauthorized traffic. It concludes that the proposed VLAN-based firewall scheme enhances network security performance.
The document discusses techniques for bypassing firewall systems. It provides background on firewall systems, describing their evolution, types, state of the art features, and risks. It then outlines various attack techniques hackers use to bypass firewalls, such as compromising external trusted systems, exploiting vulnerabilities in client software, stealing credentials through screen grabbing, and sending malicious content in files or emails that exploit software vulnerabilities when opened. The goal of these attacks is to access internal corporate networks or run attacker code on internal systems.
This document discusses the Address Resolution Protocol (ARP) and its use in intrusion detection systems. It proposes a standardized 64-byte ARP protocol structure to more easily capture ARP packets from a network. The structure includes fields for frame information, destination and source addresses, ARP type details, and sender/target MAC and IP addresses. This standardized structure could be integrated into network monitoring to help detect intrusions without affecting normal data transfer processes. Overall, the document aims to optimize the ARP sequence for use in intrusion detection systems.
This document discusses steganography, which is a method of hiding secret messages within other files or data streams. It provides definitions and examples of different types of steganography, including static steganography which hides messages in digital files, and dynamic steganography which hides messages in protocols like TCP/IP packets as they are transmitted over the internet. The document also discusses uses of steganography, such as watermarking to track copyrighted content, and concerns about potential terrorist use of steganography over the internet through covert channels. Detection of hidden messages, called steganalysis, and technology to help law enforcement monitor covert communications are also mentioned.
HIERARCHICAL DESIGN BASED INTRUSION DETECTION SYSTEM FOR WIRELESS AD HOC SENS...
In recent years, wireless ad hoc sensor network becomes popular both in civil and military jobs. However, security is one of the significant challenges for sensor network because of their deployment in open and unprotected environment. As cryptographic mechanism is not enough to protect sensor network from external attacks, intrusion detection system needs to be introduced. Though intrusion prevention mechanism is one of the major and efficient methods against attacks, but there might be some attacks for which prevention method is not known. Besides preventing the system from some known attacks, intrusion detection system gather necessary information related to attack technique and help in the development of intrusion prevention system. In addition to reviewing the present attacks available in wireless sensor network this paper examines the current efforts to intrusion detection
system against wireless sensor network. In this paper we propose a hierarchical architectural design based intrusion detection system that fits the current demands and restrictions of wireless ad hoc sensor network. In this proposed intrusion detection system architecture we followed clustering mechanism to build a four level hierarchical network which enhances network scalability to large geographical area and use both anomaly and misuse detection techniques for intrusion detection. We introduce policy based detection mechanism as well as intrusion response together with GSM cell concept for intrusion detection architecture.
This paper has provided a basic review of the notion of a network firewall and considerations regarding the requirements for deploying one in a zEnterprise environment. It has also described the internal networking support introduced with the IBM zEnterprise and how, due to its enhanced physical and logical security, in many cases it may eliminate the need for a network firewall to protect network traffic within a zEnterprise environment. Finally, it has described how you can use an external firewall if it is deemed necessary, e.g. for regulatory reasons or due to general mandated corporate policy, to utilize a specific network firewall solution to protect traffic between virtual servers in a zEnterprise environment.
Firewalls serve to filter network traffic and keep destructive forces from entering a network, similar to how fire barriers contain fires. The first firewalls were created in the 1980s and gained popularity later in the decade. Modern firewalls can be packet filters, circuit-level gateways, application-level gateways, or stateful multilayer inspection firewalls, with each generation building on the previous ones to provide stronger security but at increased complexity and cost.
Passive monitoring to build Situational AwarenessDavid Sweigert
Passive network monitoring techniques can provide valuable situational awareness for network security professionals. The document describes techniques for passively discovering information about nodes on a network, including operating systems, roles, services, and configurations. This contextual information helps analysts by reducing false positives and focusing resources. The passive approach does not disrupt networks and can operate continuously, in contrast to active scanning tools. A network monitoring prototype is being developed to test these passive discovery techniques.
This document discusses security issues related to wireless sensor networks. It begins with an introduction to wireless sensor networks and an overview of security challenges due to limited sensor node capabilities. It then summarizes common attacks on different layers of wireless sensor networks and discusses security objectives. The document outlines key areas of research on sensor network security including key management, secure time synchronization, and secure routing. It provides details on different key management schemes, time synchronization protocols, and discusses vulnerabilities of existing synchronization schemes to various attacks.
This document discusses the development of a novel pattern detection processor using an adaptively divisible dual-port BiTCAM (binary ternary content-addressable memory) to achieve high-throughput, low-power and low-cost pattern detection for mobile devices. The proposed dual-port BiTCAM architecture uses a dual-port AND-type match-line scheme with dual-port active AND gates. This allows for shared storage spaces to reduce power consumption through improved storage efficiency. The divisible BiTCAM also provides flexibility to regularly update the virus database.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IRJET - Implementation of Firewall in a Cooperate EnvironmentIRJET Journal
This document discusses the implementation of firewalls in a corporate environment. It begins with an introduction to computer security and firewalls. Firewalls regulate information flow between computer networks and protect networks by standing between the network and outside world. There are different types of firewalls such as packet filtering, stateful, circuit level gateway, and application proxy firewalls. The document then discusses the need for firewalls in corporate environments and existing firewall systems using IPv4 and IPv6. It proposes a new firewall system based on VLANs which uses virtual LANs to allow authorized groups of computers on the network while restricting unauthorized traffic. It concludes that the proposed VLAN-based firewall scheme enhances network security performance.
The document discusses techniques for bypassing firewall systems. It provides background on firewall systems, describing their evolution, types, state of the art features, and risks. It then outlines various attack techniques hackers use to bypass firewalls, such as compromising external trusted systems, exploiting vulnerabilities in client software, stealing credentials through screen grabbing, and sending malicious content in files or emails that exploit software vulnerabilities when opened. The goal of these attacks is to access internal corporate networks or run attacker code on internal systems.
This document discusses the Address Resolution Protocol (ARP) and its use in intrusion detection systems. It proposes a standardized 64-byte ARP protocol structure to more easily capture ARP packets from a network. The structure includes fields for frame information, destination and source addresses, ARP type details, and sender/target MAC and IP addresses. This standardized structure could be integrated into network monitoring to help detect intrusions without affecting normal data transfer processes. Overall, the document aims to optimize the ARP sequence for use in intrusion detection systems.
This document discusses steganography, which is a method of hiding secret messages within other files or data streams. It provides definitions and examples of different types of steganography, including static steganography which hides messages in digital files, and dynamic steganography which hides messages in protocols like TCP/IP packets as they are transmitted over the internet. The document also discusses uses of steganography, such as watermarking to track copyrighted content, and concerns about potential terrorist use of steganography over the internet through covert channels. Detection of hidden messages, called steganalysis, and technology to help law enforcement monitor covert communications are also mentioned.
HIERARCHICAL DESIGN BASED INTRUSION DETECTION SYSTEM FOR WIRELESS AD HOC SENS...IJNSA Journal
In recent years, wireless ad hoc sensor network becomes popular both in civil and military jobs. However, security is one of the significant challenges for sensor network because of their deployment in open and unprotected environment. As cryptographic mechanism is not enough to protect sensor network from external attacks, intrusion detection system needs to be introduced. Though intrusion prevention mechanism is one of the major and efficient methods against attacks, but there might be some attacks for which prevention method is not known. Besides preventing the system from some known attacks, intrusion detection system gather necessary information related to attack technique and help in the development of intrusion prevention system. In addition to reviewing the present attacks available in wireless sensor network this paper examines the current efforts to intrusion detection
system against wireless sensor network. In this paper we propose a hierarchical architectural design based intrusion detection system that fits the current demands and restrictions of wireless ad hoc sensor network. In this proposed intrusion detection system architecture we followed clustering mechanism to build a four level hierarchical network which enhances network scalability to large geographical area and use both anomaly and misuse detection techniques for intrusion detection. We introduce policy based detection mechanism as well as intrusion response together with GSM cell concept for intrusion detection architecture.
This paper has provided a basic review of the notion of a network firewall and considerations regarding the requirements for deploying one in a zEnterprise environment. It has also described the internal networking support introduced with the IBM zEnterprise and how, due to its enhanced physical and logical security, in many cases it may eliminate the need for a network firewall to protect network traffic within a zEnterprise environment. Finally, it has described how you can use an external firewall if it is deemed necessary, e.g. for regulatory reasons or due to general mandated corporate policy, to utilize a specific network firewall solution to protect traffic between virtual servers in a zEnterprise environment.
Mobile ad hoc networks (MANETs) are collections of self-organizing mobile nodes with dynamic topologies and no centralized authority. Each node participating in the network acts both as host and a router. So each node can participate to transfer data packet to destination node but suppose one node in network is removed at time it is very difficult to maintain the information about all node. The main advantage and disadvantage of MANETs provides large number of degree of freedom and self-organizing capability of that make it completely different from other network. Due to the nature of MANETs, to design and development of secure routing is challenging task for researcher in an open and distributed communication environments. In MANET, the more security is required in comparison to wired network. If source node chooses this fake route, malicious nodes have the option of delivering the packets or dropping them.
Keywords: MANETs, Security, Cryptography.
Analysis of security threats in wireless sensor networkijwmn
Wireless Sensor Network(WSN) is an emerging technology and explored field of researchers worldwide
in the past few years, so does the need for effective security mechanisms. The sensing technology
combined with processing power and wireless communication makes it lucrative for being exploited in
abundance in future. The inclusion of wireless communication technology also incurs various types of
security threats due to unattended installation of sensor nodes as sensor networks may interact with
sensitive data and /or operate in hostile unattended environments. These security concerns be addressed
from the beginning of the system design. The intent of this paper is to investigate the security related
issues in wireless sensor networks. In this paper we have explored general security threats in wireless
sensor network with extensive study.
EWSN'15 Industry Session - Francesco Flammini (Ansaldo STS)Francesco Flammini
Ansaldo STS (Francesco Flammini) contribution to the industry session of the European conference on Wireless Sensor Networks (EWSN 2015, Porto, Portugal)
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document summarizes a seminar on computer network security given on November 22, 2012. It discusses the OSI model layers and security perspectives for each layer. The layers covered are the physical, data link, network, transport, session, presentation, and application layers. Common attacks are listed for each layer such as packet sniffing for the data link layer and SQL injection for the application layer. The document concludes with a reminder that social engineering is also an important security issue.
The document outlines a new standard operating procedure for the intake process of new patients at a VA healthcare system in Long Beach, California. The procedure aims to improve efficiency by assigning new veterans to a primary care team and scheduling an initial appointment. Key steps include the intake nurse reviewing patient information, discussing primary care options, completing intake questionnaires, screening for health issues, and scheduling the first appointment using an appointment management system. If the intake nurse is unavailable, medical support staff and nurses will assist by collecting patient information and handling the intake duties.
Bharti Airtel is the largest cellular service provider in India with a 21% market share. Founded in 1995, it has over 261 million subscribers across 20 countries. As the leading cellular service provider in India, Airtel offers 2G, 3G, and other services. It provides national and international long distance services for carriers and has launched initiatives like Airtel Money for mobile payments. The document discusses Airtel's products, competitors in the Indian market, network infrastructure, and potential acquisitions.
MDAC is a framework that allows developers to access data stores uniformly. It consists of ADO, OLE DB, and ODBC components. MDAC architecture includes three layers: a programming interface (ADO/ADO.NET), a database access layer provided by vendors, and the database. OLE DB allows uniform data store access. ODBC provides a native interface through which drivers access specific databases. ADO is a high-level interface that uses OLE DB. It consists of objects and collections that allow creating, retrieving, updating and deleting data.
This standard operating procedure outlines Precision Electronics Limited's information security policies and procedures. It details the appointment of a Chief Information Security Officer to oversee security measures. It also covers required staff training, annual security audits, protection of networks, applications, data and devices, and forms to adhere to security guidelines. Any violations of this policy may result in disciplinary action up to and including termination of employment.
Bharti Airtel is the largest cellular service provider in India with a 21% market share. Founded in 1995, it has over 261 million subscribers across 20 countries. As the leading cellular service provider in India, Airtel offers 2G, 3G, and other services. It provides national and international long distance services for carriers and has launched initiatives like Airtel Money for mobile payments. The document discusses Airtel's products, competitors in the Indian market, network infrastructure, and potential acquisitions.
This document outlines security procedures for an office. It details 7 steps for security guards: 1) reporting for duty, 2) parking assistance, 3) monitoring employee entry/exit with ID checks, 4) visitor admittance with logging, 5) random checks for devices, 6) replacing guards during breaks, and 7) monitoring employee exits and locking up. The procedures focus on access control, visitor management, and general security duties like greeting employees and ensuring the phone is charged.
These are basic skill set, duty responsibility and his ability to do the assigned work. The requirement of client is also mentioned to make process proper.
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.
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 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, 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.
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.
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.
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.
ppt consists of history, generations of firewalls, types, architectures, advantages & disadvantages.
very basic ppt- can be used for college & paper presentation seminars.
This document discusses firewall design and implementation issues. It begins by explaining the origin of firewalls as a response to growing security concerns online. It then defines what a firewall is and discusses the need for firewalls to block unauthorized access and protect networks. The document outlines the history of firewalls and describes the main types: packet filtering, circuit-level gateways, and application-level firewalls. It addresses design considerations like policy, traffic control, and costs. In conclusion, it stresses the importance of firewalls for all connected organizations and choosing a solution tailored to needs.
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.
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
Firewalls have evolved from metal sheets used in the 19th century to protect buildings from fire, to software and hardware used today to filter network traffic and protect computers and networks. Key developments included the growth of the internet in the 1980s which led to the implementation of firewalls in routers to control network data traffic and allocate networks. Different types of firewalls evolved to suit various network sizes, from personal firewalls on individual computers to enterprise firewalls capable of handling thousands of users across multiple firewalls. Future firewalls may be integrated directly into devices like personal computers and supercomputers.
The document discusses firewalls and their implementation, providing details on different types of firewalls like network layer packet filters, application layer proxies, and network address translation firewalls. It also describes different implementations of firewalls including transparent/bridging firewalls, sandwich firewalls, and VLAN switch implementations. The document then focuses on Cisco PIX firewalls, providing details on their architecture, operation, and hardware.
Firewall is a network security device that monitors incoming and outgoing network traffic and filters it based on predefined security rules. It establishes a barrier between internal secure networks and external untrusted networks like the internet. There are different types of firewalls including packet filtering, stateful inspection, and application-level firewalls. Firewalls provide advantages like network reliability, simplicity of implementation, and cost-effectiveness. However, they also have disadvantages such as potential performance issues and not providing other security features like antivirus. Education is needed on firewall security automation and processes to improve business efficiency.
A firewall monitors incoming and outgoing network traffic and blocks or permits data packets based on security rules. There are several types of firewalls including packet-filtering firewalls, circuit-level gateways, stateful inspection firewalls, application-level gateways, next-gen firewalls, software firewalls, and hardware firewalls. Cloud firewalls provide firewall services through a cloud-based solution and are easy to scale with organizational needs.
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.
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.
The document discusses data security in local networks using distributed firewalls. It describes how distributed firewalls work to overcome issues with traditional firewalls, which rely on a single entry point. Distributed firewalls are centrally managed from a network server but installed on endpoints throughout the network. This allows security policies to be defined and pushed centrally while filtering traffic both from the internet and internally. It also discusses how distributed firewalls use pull and push techniques to update endpoints with the latest security policies from the central management server.
Firewalls monitor and filter network traffic based on security policies. There are different types of firewalls that use various methods like packet filtering, application-level gateways, stateful inspection, and more. Firewalls are necessary to protect networks from threats and work by allowing approved traffic while blocking dangerous traffic according to pre-set policies. They defend networks by detecting and responding to malware and other attacks across the entire system.
This document provides an overview of mobile ad hoc networks (MANETs) and several routing protocols used in MANETs. It defines MANETs and their characteristics. It then describes several representative routing protocols, including reactive (AODV, DSR), proactive (DSDV, TBRPF) protocols. It compares these protocols through simulations on metrics like packet delivery ratio, end-to-end delay, routing overhead under different traffic loads and node mobility. It finds that no single protocol performs best under all conditions and that fundamental open questions around scalability, energy efficiency and security remain.
This document provides a summary of routing protocols in mobile ad hoc networks (MANETs). It begins with an introduction to MANETs and their characteristics. It then discusses why traditional routing protocols are not suitable for MANETs and describes some common MANET routing protocols, classifying them as proactive (table-driven) or reactive (on-demand). Specifically, it provides detailed descriptions of the reactive protocols DSR and AODV, covering topics like route discovery, maintenance, and deletion. Finally, it compares these protocols and discusses which may be better suited under different network conditions.
Lightweight Directory Access Protocol (LDAP) is a networking protocol for querying and modifying directory services running over TCP/IP. LDAP was designed to provide directory services in a simpler way than X.500 by running directly over TCP and using simplified data representations. The core LDAP operations include search, add, delete, modify, modify RDN, bind, unbind, and abandon. LDAP follows the X.500 model of a hierarchical tree structure of directory entries made up of attributes.
Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to enable virtual private networks over the public Internet. L2TP merges features of PPTP and L2F to encapsulate PPP frames for transmission over an IP network. The L2TP Access Concentrator terminates the user connection and tunnels individual PPP frames to the L2TP Network Server, which processes the PPP session separately from the physical connection termination point. L2TP allows VPN endpoints to be located on different machines and eliminates possible long-distance charges.
The document discusses interactive voice response (IVR) systems. It provides an overview of what an IVR system is and how it allows callers to interact with automated menus and retrieve information from databases without speaking to a human agent. It describes the key components of an IVR system, including its call handling engine and application generator software. It also lists some of the main features and benefits that Insight IVR systems provide, such as web-based reporting, unlimited call flows, text-to-speech, and speech recognition capabilities.
IPsec is a standardized framework that provides security (encryption, authentication, integrity) for IP communications. It has two modes - Transport mode which encrypts only the payload, and Tunnel mode which encrypts both the header and payload. IPsec uses protocols like AH (Authentication Header) which provides authentication and integrity, and ESP (Encapsulating Security Payload) which provides confidentiality, authentication, and integrity. IPsec implementations can be in end hosts or routers depending on network requirements.
The iPod is Apple's popular digital audio player introduced in 2001. It uses a central scroll wheel interface and stores music on an internal hard drive or flash memory. The iPod plays many audio formats and works with the iTunes software to transfer music from computers. Later models added video playback. While very popular, the iPod has faced some criticism around non-replaceable batteries, potential hearing loss from loud volumes, and reports of worker exploitation in its manufacturing facilities.
The document provides an overview of the history and development of the Internet. It discusses how the Internet began as a US military program called ARPANET in the 1960s and expanded to include academic and research networks. By the 1980s, the TCP/IP protocol allowed different networks to interconnect, and the term "Internet" was adopted. In the 1990s, the World Wide Web brought the Internet to the general public. The document also describes the basic infrastructure of the Internet including protocols, network structures, and governance organizations like ICANN.
The document provides information on various techniques for image compression, including lossless and lossy compression methods. For lossless compression, it describes run-length encoding, entropy coding, and area coding. For lossy compression it discusses reducing the color space, chroma subsampling, and transform coding using DCT and wavelets. It also covers segmentation/approximation methods, spline interpolation, fractal coding, and bit allocation techniques for optimal compression.
This document discusses Intel's Hyper-Threading Technology, which allows a single physical processor core to appear and function as two logical processors to the operating system. It does this by duplicating the core's architectural state and partitioning its execution resources between the two logical processors. This allows both logical processors to execute instructions simultaneously by sharing execution units, caches, and other resources. The document provides details on how the front-end, execution engine, registers, buffers, caches and other components function for both logical processors simultaneously through partitioning, duplication, and alternating access between the two threads.
- HTML was created by Tim Berners-Lee in the late 1980s and early 1990s to allow information sharing through hypertext links on the then-emerging World Wide Web. It uses tags to define the structure and layout of webpages and allows multimedia content.
- The basic structure of an HTML document involves tags like <html> to open and close the HTML document, <head> to contain metadata, <title> to define the title, and <body> to contain the visible page content.
- Common text formatting is done using tags like <h1> for main headings, <p> for paragraphs, and <font> to specify font attributes. Lists are created with <ul> for unordered
This document provides an overview of HTML and DHTML. It discusses the history of HTML, including its creation by Tim Berners-Lee in the 1980s using SGML. It defines HTML as a language used to structure and format web pages through markup tags. The document lists some popular HTML editors and covers basic HTML topics like creating web pages, URLs, and viewing pages in browsers. It concludes with definitions of HTML as a markup language rather than a programming language, used to format text and information with tags.
The document discusses the role of a database administrator (DBA). A DBA is responsible for managing an organization's database structure, including physical database design, security, performance, backups and recovery. Key responsibilities of a DBA include establishing data policies and standards, planning the database infrastructure, resolving data conflicts, promoting data standards internally, and managing the information repository and selection of hardware/software.
1. Display systems are used in a wide variety of consumer electronics and industrial applications ranging from small devices like watches to large displays used in public spaces.
2. There are two main types of display systems - direct view systems which users view directly, and projection systems which first create an image on an internal screen and project it onto a larger external screen.
3. The display industry in India is growing but there is still a need for increased public awareness of the technology and its uses across different industries.
This document discusses honeypots, which are fake computer systems designed to attract hackers. Honeypots monitor the activity of hackers and collect data on their tactics. They are classified based on their level of interaction (low or high) and implementation environment (research or production). Honeypots provide advantages like detecting new hacking tools and minimizing resources needed. They also have disadvantages like limited visibility and risk of being hijacked. The document discusses practical applications of honeypots for preventing attacks, detecting intrusions, and conducting cyber forensics investigations.
Honeypots are security tools that allow systems to be monitored, analyzed and defended. They work by emulating vulnerabilities to attract hackers and observe their behavior without exposing real systems to harm. There are different types of honeypots based on level of interaction, from low to high. Low interaction honeypots like Honeyd emulate services with limited functionality while high interaction ones like Honeynets create fully functional virtual systems. Honeypots provide benefits like reduced false alarms, new threat intelligence and forensic data but also have drawbacks like single data points and fingerprinting risks. They are useful for research, detection and prevention when used carefully alongside other security practices.
The document discusses honeypots, which are decoy computer systems used to detect cyber attacks. It describes two main types of honeypots: low-interaction honeypots, which emulate services and operating systems, and high-interaction honeypots, which use real systems and software. Low-interaction honeypots are easier to deploy but provide limited information, while high-interaction honeypots provide more complete data but also higher risks if not isolated properly. Specific honeypot examples discussed include Honeyd, a low-interaction honeypot, and Honeynets, which use entire decoy networks of high-interaction systems.
This document proposes a honeypot architecture to detect and analyze unknown network attacks. The architecture combines three main components: 1) a packet filter that suppresses known attack packets, 2) a proxy host that logs network traffic at the session level, and 3) a honeypot host that executes actual network services in a supervised environment and reports suspicious behavior to the proxy host. Experiences with a prototype show it is possible to specify and identify suspicious traffic belonging to attacks.
Haptic technology, also known as force-feedback technology, uses the sense of touch through receptors in the skin, muscles, and joints. There are two groups of touch receptors: kinesthetic receptors in the tendons, muscles, and joints and tactile receptors in the dermis and epidermis. Haptic devices can provide haptic feedback and be used for medical training applications to increase accuracy, for stroke patients to interact with virtual worlds through touch, and to measure forces during minimally invasive surgery.
Haptic technology adds the sense of touch to virtual environments through haptic interfaces. This allows users to feel virtual objects on a computer through forces, vibrations, and motions. Haptic interfaces track user movements and apply forces through motors. Haptic rendering algorithms compute interaction forces between virtual objects and the user's movements in real-time. Applications include medical training simulations, remote robotics, virtual prototyping, and assisting those with disabilities.
Best Programming Language for Civil EngineersAwais Yaseen
The integration of programming into civil engineering is transforming the industry. We can design complex infrastructure projects and analyse large datasets. Imagine revolutionizing the way we build our cities and infrastructure, all by the power of coding. Programming skills are no longer just a bonus—they’re a game changer in this era.
Technology is revolutionizing civil engineering by integrating advanced tools and techniques. Programming allows for the automation of repetitive tasks, enhancing the accuracy of designs, simulations, and analyses. With the advent of artificial intelligence and machine learning, engineers can now predict structural behaviors under various conditions, optimize material usage, and improve project planning.
UiPath Community Day Kraków: Devs4Devs ConferenceUiPathCommunity
We are honored to launch and host this event for our UiPath Polish Community, with the help of our partners - Proservartner!
We certainly hope we have managed to spike your interest in the subjects to be presented and the incredible networking opportunities at hand, too!
Check out our proposed agenda below 👇👇
08:30 ☕ Welcome coffee (30')
09:00 Opening note/ Intro to UiPath Community (10')
Cristina Vidu, Global Manager, Marketing Community @UiPath
Dawid Kot, Digital Transformation Lead @Proservartner
09:10 Cloud migration - Proservartner & DOVISTA case study (30')
Marcin Drozdowski, Automation CoE Manager @DOVISTA
Pawel Kamiński, RPA developer @DOVISTA
Mikolaj Zielinski, UiPath MVP, Senior Solutions Engineer @Proservartner
09:40 From bottlenecks to breakthroughs: Citizen Development in action (25')
Pawel Poplawski, Director, Improvement and Automation @McCormick & Company
Michał Cieślak, Senior Manager, Automation Programs @McCormick & Company
10:05 Next-level bots: API integration in UiPath Studio (30')
Mikolaj Zielinski, UiPath MVP, Senior Solutions Engineer @Proservartner
10:35 ☕ Coffee Break (15')
10:50 Document Understanding with my RPA Companion (45')
Ewa Gruszka, Enterprise Sales Specialist, AI & ML @UiPath
11:35 Power up your Robots: GenAI and GPT in REFramework (45')
Krzysztof Karaszewski, Global RPA Product Manager
12:20 🍕 Lunch Break (1hr)
13:20 From Concept to Quality: UiPath Test Suite for AI-powered Knowledge Bots (30')
Kamil Miśko, UiPath MVP, Senior RPA Developer @Zurich Insurance
13:50 Communications Mining - focus on AI capabilities (30')
Thomasz Wierzbicki, Business Analyst @Office Samurai
14:20 Polish MVP panel: Insights on MVP award achievements and career profiling
The DealBook is our annual overview of the Ukrainian tech investment industry. This edition comprehensively covers the full year 2023 and the first deals of 2024.
Mitigating the Impact of State Management in Cloud Stream Processing SystemsScyllaDB
Stream processing is a crucial component of modern data infrastructure, but constructing an efficient and scalable stream processing system can be challenging. Decoupling compute and storage architecture has emerged as an effective solution to these challenges, but it can introduce high latency issues, especially when dealing with complex continuous queries that necessitate managing extra-large internal states.
In this talk, we focus on addressing the high latency issues associated with S3 storage in stream processing systems that employ a decoupled compute and storage architecture. We delve into the root causes of latency in this context and explore various techniques to minimize the impact of S3 latency on stream processing performance. Our proposed approach is to implement a tiered storage mechanism that leverages a blend of high-performance and low-cost storage tiers to reduce data movement between the compute and storage layers while maintaining efficient processing.
Throughout the talk, we will present experimental results that demonstrate the effectiveness of our approach in mitigating the impact of S3 latency on stream processing. By the end of the talk, attendees will have gained insights into how to optimize their stream processing systems for reduced latency and improved cost-efficiency.
Are you interested in dipping your toes in the cloud native observability waters, but as an engineer you are not sure where to get started with tracing problems through your microservices and application landscapes on Kubernetes? Then this is the session for you, where we take you on your first steps in an active open-source project that offers a buffet of languages, challenges, and opportunities for getting started with telemetry data.
The project is called openTelemetry, but before diving into the specifics, we’ll start with de-mystifying key concepts and terms such as observability, telemetry, instrumentation, cardinality, percentile to lay a foundation. After understanding the nuts and bolts of observability and distributed traces, we’ll explore the openTelemetry community; its Special Interest Groups (SIGs), repositories, and how to become not only an end-user, but possibly a contributor.We will wrap up with an overview of the components in this project, such as the Collector, the OpenTelemetry protocol (OTLP), its APIs, and its SDKs.
Attendees will leave with an understanding of key observability concepts, become grounded in distributed tracing terminology, be aware of the components of openTelemetry, and know how to take their first steps to an open-source contribution!
Key Takeaways: Open source, vendor neutral instrumentation is an exciting new reality as the industry standardizes on openTelemetry for observability. OpenTelemetry is on a mission to enable effective observability by making high-quality, portable telemetry ubiquitous. The world of observability and monitoring today has a steep learning curve and in order to achieve ubiquity, the project would benefit from growing our contributor community.
Paradigm Shifts in User Modeling: A Journey from Historical Foundations to Em...Erasmo Purificato
Slide of the tutorial entitled "Paradigm Shifts in User Modeling: A Journey from Historical Foundations to Emerging Trends" held at UMAP'24: 32nd ACM Conference on User Modeling, Adaptation and Personalization (July 1, 2024 | Cagliari, Italy)
Fluttercon 2024: Showing that you care about security - OpenSSF Scorecards fo...Chris Swan
Have you noticed the OpenSSF Scorecard badges on the official Dart and Flutter repos? It's Google's way of showing that they care about security. Practices such as pinning dependencies, branch protection, required reviews, continuous integration tests etc. are measured to provide a score and accompanying badge.
You can do the same for your projects, and this presentation will show you how, with an emphasis on the unique challenges that come up when working with Dart and Flutter.
The session will provide a walkthrough of the steps involved in securing a first repository, and then what it takes to repeat that process across an organization with multiple repos. It will also look at the ongoing maintenance involved once scorecards have been implemented, and how aspects of that maintenance can be better automated to minimize toil.
Implementations of Fused Deposition Modeling in real worldEmerging Tech
The presentation showcases the diverse real-world applications of Fused Deposition Modeling (FDM) across multiple industries:
1. **Manufacturing**: FDM is utilized in manufacturing for rapid prototyping, creating custom tools and fixtures, and producing functional end-use parts. Companies leverage its cost-effectiveness and flexibility to streamline production processes.
2. **Medical**: In the medical field, FDM is used to create patient-specific anatomical models, surgical guides, and prosthetics. Its ability to produce precise and biocompatible parts supports advancements in personalized healthcare solutions.
3. **Education**: FDM plays a crucial role in education by enabling students to learn about design and engineering through hands-on 3D printing projects. It promotes innovation and practical skill development in STEM disciplines.
4. **Science**: Researchers use FDM to prototype equipment for scientific experiments, build custom laboratory tools, and create models for visualization and testing purposes. It facilitates rapid iteration and customization in scientific endeavors.
5. **Automotive**: Automotive manufacturers employ FDM for prototyping vehicle components, tooling for assembly lines, and customized parts. It speeds up the design validation process and enhances efficiency in automotive engineering.
6. **Consumer Electronics**: FDM is utilized in consumer electronics for designing and prototyping product enclosures, casings, and internal components. It enables rapid iteration and customization to meet evolving consumer demands.
7. **Robotics**: Robotics engineers leverage FDM to prototype robot parts, create lightweight and durable components, and customize robot designs for specific applications. It supports innovation and optimization in robotic systems.
8. **Aerospace**: In aerospace, FDM is used to manufacture lightweight parts, complex geometries, and prototypes of aircraft components. It contributes to cost reduction, faster production cycles, and weight savings in aerospace engineering.
9. **Architecture**: Architects utilize FDM for creating detailed architectural models, prototypes of building components, and intricate designs. It aids in visualizing concepts, testing structural integrity, and communicating design ideas effectively.
Each industry example demonstrates how FDM enhances innovation, accelerates product development, and addresses specific challenges through advanced manufacturing capabilities.
Sustainability requires ingenuity and stewardship. Did you know Pigging Solutions pigging systems help you achieve your sustainable manufacturing goals AND provide rapid return on investment.
How? Our systems recover over 99% of product in transfer piping. Recovering trapped product from transfer lines that would otherwise become flush-waste, means you can increase batch yields and eliminate flush waste. From raw materials to finished product, if you can pump it, we can pig it.
Quality Patents: Patents That Stand the Test of TimeAurora Consulting
Is your patent a vanity piece of paper for your office wall? Or is it a reliable, defendable, assertable, property right? The difference is often quality.
Is your patent simply a transactional cost and a large pile of legal bills for your startup? Or is it a leverageable asset worthy of attracting precious investment dollars, worth its cost in multiples of valuation? The difference is often quality.
Is your patent application only good enough to get through the examination process? Or has it been crafted to stand the tests of time and varied audiences if you later need to assert that document against an infringer, find yourself litigating with it in an Article 3 Court at the hands of a judge and jury, God forbid, end up having to defend its validity at the PTAB, or even needing to use it to block pirated imports at the International Trade Commission? The difference is often quality.
Quality will be our focus for a good chunk of the remainder of this season. What goes into a quality patent, and where possible, how do you get it without breaking the bank?
** Episode Overview **
In this first episode of our quality series, Kristen Hansen and the panel discuss:
⦿ What do we mean when we say patent quality?
⦿ Why is patent quality important?
⦿ How to balance quality and budget
⦿ The importance of searching, continuations, and draftsperson domain expertise
⦿ Very practical tips, tricks, examples, and Kristen’s Musts for drafting quality applications
https://www.aurorapatents.com/patently-strategic-podcast.html
RPA In Healthcare Benefits, Use Case, Trend And Challenges 2024.pptxSynapseIndia
Your comprehensive guide to RPA in healthcare for 2024. Explore the benefits, use cases, and emerging trends of robotic process automation. Understand the challenges and prepare for the future of healthcare automation
BT & Neo4j: Knowledge Graphs for Critical Enterprise Systems.pptx.pdfNeo4j
Presented at Gartner Data & Analytics, London Maty 2024. BT Group has used the Neo4j Graph Database to enable impressive digital transformation programs over the last 6 years. By re-imagining their operational support systems to adopt self-serve and data lead principles they have substantially reduced the number of applications and complexity of their operations. The result has been a substantial reduction in risk and costs while improving time to value, innovation, and process automation. Join this session to hear their story, the lessons they learned along the way and how their future innovation plans include the exploration of uses of EKG + Generative AI.
Measuring the Impact of Network Latency at TwitterScyllaDB
Widya Salim and Victor Ma will outline the causal impact analysis, framework, and key learnings used to quantify the impact of reducing Twitter's network latency.
Understanding Insider Security Threats: Types, Examples, Effects, and Mitigat...Bert Blevins
Today’s digitally connected world presents a wide range of security challenges for enterprises. Insider security threats are particularly noteworthy because they have the potential to cause significant harm. Unlike external threats, insider risks originate from within the company, making them more subtle and challenging to identify. This blog aims to provide a comprehensive understanding of insider security threats, including their types, examples, effects, and mitigation techniques.
論文紹介:A Systematic Survey of Prompt Engineering on Vision-Language Foundation ...Toru Tamaki
Jindong Gu, Zhen Han, Shuo Chen, Ahmad Beirami, Bailan He, Gengyuan Zhang, Ruotong Liao, Yao Qin, Volker Tresp, Philip Torr "A Systematic Survey of Prompt Engineering on Vision-Language Foundation Models" arXiv2023
https://arxiv.org/abs/2307.12980
Blockchain technology is transforming industries and reshaping the way we conduct business, manage data, and secure transactions. Whether you're new to blockchain or looking to deepen your knowledge, our guidebook, "Blockchain for Dummies", is your ultimate resource.
1. FIREWALL
Introduction
A firewall is an information technology (IT) security device which is configured to
permit, deny or proxy data connections set and configured by the organization's security
policy. Firewalls can either be hardware and/or software based.
A firewall's basic task is to control traffic between computer networks with different
zones of trust. Typical examples are the Internet which is a zone with no trust and an
internal network which is (and should be) a zone with high trust. The ultimate goal is to
provide controlled interfaces between zones of differing trust levels through the
enforcement of a security policy and connectivity model based on the least privilege
principle and separation of duties.
A firewall is also called a Border Protection Device (BPD) in certain military contexts
were a firewall separates networks by creating perimeter networks in a DMZ. In a BSD
context they are also known as a packet filter. A firewall's function is analogous to
firewalls in building construction.
Proper configuration of firewalls demands skill from the firewall administrator. It requires
considerable understanding of network protocols and of computer security. Small mistakes
can render a firewall worthless as a security tool.
History
Firewall technology emerged in the late 1980s when the Internet was a fairly new
technology in terms of its global use and connectivity. The original idea was formed in
response to a number of major internet security breaches, which occurred in the late
1980s. 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
1
2. NASA Ames." This virus known as the Morris Worm was carried by e-mail. 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 Jeff Mogul from
Digital Equipment Corporation (DEC) developed filter systems known as packet filter
firewalls. This fairly basic system was the first generation of what would become a
highly evolved and technical internet security feature. At AT&T Bill Cheswick and Steve
Bellovin were continuing their research in packet filtering and developed a working
model for their own company based upon their original first generation architecture.
Second generation - circuit level
From 1980-1990 two colleagues from AT&T Bell Laboratories, Dave Presetto and
Howard Trickey, developed the second generation of firewalls known as circuit level
firewalls.
Third generation - applicaton layer
Publications by Gene Spafford of Purdue University, Bill Cheswick at AT&T
Laboratories and Marcus Ranum described a third generation firewall known as
application layer firewall, also known as proxy based firewalls. Marcus Ranum's work
on the technology spearheaded the creation of the first commercial product. The product
was released by DEC who named it the SEAL product. DEC’s first major sale was on
June 13, 1991 to a chemical company based on the East Coast of the USA.
Subsequent generations
In 1992, Bob Braden and Annette DeSchon at the University of Southern California
(USC) were developing their own fourth generation packet filter firewall system. The
product known as “Visas” was the first system to have a visual integration interface with
2
3. colours and icons, which could be easily implemented to and accessed on a computer
operating system such as Microsoft's Windows or Apple's MacOS. In 1994 an Israeli
company called Check Point Software Technologies built this into readily available
software known as FireWall-1.
A second generation of proxy firewalls was based on Kernel Proxy technology. This
design is constantly evolving but its basic features and codes are currently in widespread
use in both commercial and domestic computer systems. Cisco, one of the largest internet
security companies in the world released their PIX product to the public in 1997.
The new Next Generation Firewalls leverage their existing deep packet inspection engine
by sharing this functionality with an Intrusion-prevention system (IPS).
Types
There are three basic types of firewalls depending on:
1. Whether the communication is being done between a single node and the
network, or between two or more networks.
2. Whether the communication is intercepted at the network layer, or at the
application layer.
3. Whether the communication state is being tracked at the firewall or not.
With regard to the scope of filtered communications there exist:
1. Personal firewalls, a software application which normally filters traffic entering or
leaving a single computer.
2. Network firewalls, normally running on a dedicated network device or computer
positioned on the boundary of two or more networks or DMZs (demilitarized
zones). Such a firewall filters all traffic entering or leaving the connected
networks.
3
4. The latter definition corresponds to the conventional, traditional meaning of "firewall" in
networking.
In reference to the layers where the traffic can be intercepted, three main categories of
firewalls exist:
1. Network layer firewalls. An example would be iptables.
2. Application layer firewalls. An example would be TCP Wrappers.
3. Application firewalls. An example would be restricting ftp services through
/etc/ftpaccess file
These network-layer and application-layer types of firewall may overlap, even though the
personal firewall does not serve a network; indeed, single systems have implemented
both together.
There's also the notion of application firewalls which are sometimes used during wide
area network (WAN) networking on the world-wide web and govern the system software.
An extended description would place them lower than application layer firewalls, indeed
at the Operating System layer, and could alternately be called operating system firewalls.
Lastly, depending on whether the firewalls keeps track of the state of network
connections or treats each packet in isolation, two additional categories of firewalls exist:
1. Stateful firewalls
2. Stateless firewalls
Network layer
Network layer firewalls operate at a (relatively) low level of the TCP/IP protocol stack as
IP-packet filters, not allowing packets to pass through the firewall unless they match the
rules. The firewall administrator may define the rules; or default built-in rules may apply
(as in some inflexible firewall systems).
4
5. A more permissive setup could allow any packet to pass the filter as long as it does not
match one or more "negative-rules", or "deny rules". Today network firewalls are built
into most computer operating systems and network appliances.
Modern firewalls can filter traffic based on many packet attributes like source IP address,
source port, destination IP address or port, destination service like WWW or FTP. They
can filter based on protocols, TTL values, netblock of originator, domain name of the
source, and many other attributes.
Application-layer
Application-layer firewalls work on the application level of the TCP/IP stack (i.e., all
browser traffic, or all telnet or ftp traffic), and may intercept all packets traveling to or
from an application. They block other packets (usually dropping them without
acknowledgement to the sender). In principle, application firewalls can prevent all
unwanted outside traffic from reaching protected machines.
By inspecting all packets for improper content, firewalls can even prevent the spread of
the likes of viruses. In practice, however, this becomes so complex and so difficult to
attempt (given the variety of applications and the diversity of content each may allow in
its packet traffic) that comprehensive firewall design does not generally attempt this
approach.
The XML firewall exemplifies a more recent kind of application-layer firewall.
Proxies
A proxy device (running either on dedicated hardware or as software on a general-
purpose machine) may act as a firewall by responding to input packets (connection
requests, for example) in the manner of an application, whilst blocking other packets.
Proxies make tampering with an internal system from the external network more difficult
and misuse of one internal system would not necessarily cause a security breach
5
6. exploitable from outside the firewall (as long as the application proxy remains intact and
properly configured). Conversely, intruders may hijack a publicly-reachable system and
use it as a proxy for their own purposes; the proxy then masquerades as that system to
other internal machines. While use of internal address spaces enhances security, crackers
may still employ methods such as IP spoofing to attempt to pass packets to a target
network..
Network address translation
Firewalls often have network address translation (NAT) functionality, and the hosts
protected behind a firewall commonly have addresses in the "private address range", as
defined in RFC 1918. Firewalls often have such functionality to hide the true address of
protected hosts.
Management
The Middlebox Communication (midcom) Working Group of the Internet Engineering
Task Force (IETF) is working on standardizing protocols for managing firewalls and
other middleboxes.
• Middlebox Communications (MIDCOM) Protocol Semantics
Working Of Firewall
If you have been using the Internet for any length of time, and especially if you work at a
larger company and browse the Web while you are at work, you have probably heard the
term firewall used. For example, you often hear people in companies say things like, "I
can't use that site because they won't let it through the firewall."
6
7. If you have a fast Internet connection into your home (either a DSL connection or a cable
modem), you may have found yourself hearing about firewalls for your home network as
well. It turns out that a small home network has many of the same security issues that a
large corporate network does. You can use a firewall to protect your home network and
family from offensive Web sites and potential hackers.
Basically, a firewall is a barrier to keep destructive forces away from your property. In
fact, that's why its called a firewall. Its job is similar to a physical firewall that keeps a
fire from spreading from one area to the next. As you read through this article, you will
learn more about firewalls, how they work and what kinds of threats they can protect you
from.
What It Does
A firewall is simply a program or hardware device that filters the Information coming
through the Internet connection into your private network or computer system. If an
incoming packet of information is flagged by the filters, it is not allowed through.
If you have read the article How Web Servers Work, then you know a good bit about how
data moves on the Internet, and you can easily see how a firewall helps protect computers
7
8. inside a large company. Let's say that you work at a company with 500 employees. The
company will therefore have hundreds of computers that all have network cards connecting
them together. In addition, the company will have one or more connections to the Internet
through something like T1 or T3 lines. Without a firewall in place, all of those hundreds of
computers are directly accessible to anyone on the Internet. A person who knows what he
or she is doing can probe those computers, try to make FTP connections to them, try to
make telnet connections to them and so on. If one employee makes a mistake and leaves a
security hole, hackers can get to the machine and exploit the hole.
With a firewall in place, the landscape is much different. A company will place a firewall at
every connection to the Internet (for example, at every T1 line coming into the company).
The firewall can implement security rules. For example, one of the security rules inside the
company might be:
Out of the 500 computers inside this company, only one of them is permitted to
receive public FTP traffic. Allow FTP connections only to that one computer and
prevent them on all others.
A company can set up rules like this for FTP servers, Web servers, Telnet servers and so
on. In addition, the company can control how employees connect to Web sites, whether
files are allowed to leave the company over the network and so on. A firewall gives a
company tremendous control over how people use the network.
Firewalls use one or more of three methods to control traffic flowing in and out of the
network:
1. Packet filtering - Packets (small chunks of data) are analyzed against a set of
filters. Packets that make it through the filters are sent to the requesting system
and all others are discarded.
2. Proxy service - Information from the Internet is retrieved by the firewall and then
sent to the requesting system and vice versa.
3. Stateful inspection - A newer method that doesn't examine the contents of each
packet but instead compares certain key parts of the packet to a database of
8
9. trusted information. Information traveling from inside the firewall to the outside is
monitored for specific defining characteristics, then incoming information is
compared to these characteristics. If the comparison yields a reasonable match,
the information is allowed through. Otherwise it is discarded.
Making the Firewall Fit
1. Firewalls are customizable. This means that you can add or remove filters based
on several conditions. Some of these are:
2. IP addresses - Each machine on the Internet is assigned a unique address called an
IP address. IP addresses are 32-bit numbers, normally expressed as four "octets"
in a "dotted decimal number." A typical IP address looks like this: 216.27.61.137.
For example, if a certain IP address outside the company is reading too many files
from a server, the firewall can block all traffic to or from that IP address.
3. Domain names - Because it is hard to remember the string of numbers that make
up an IP address, and because IP addresses sometimes need to change, all servers
on the Internet also have human-readable names, called domain names. For
example, it is easier for most of us to remember www.howstuffworks.com than it
is to remember 216.27.61.137. A company might block all access to certain
domain names, or allow access only to specific domain names.
4. Protocols - The protocol is the pre-defined way that someone who wants to use a
service talks with that service. The "someone" could be a person, but more often it
is a computer program like a Web browser. Protocols are often text, and simply
describe how the client and server will have their conversation. The http in the
Web's protocol. Some common protocols that you can set firewall filters for
include:
1. IP (Internet Protocol) - the main delivery system for information over the
Internet
2. TCP (Transmission Control Protocol) - used to break apart and rebuild
information that travels over the Internet
3. HTTP (Hyper Text Transfer Protocol) - used for Web pages
9
10. 4. FTP (File Transfer Protocol) - used to download and upload files
5. UDP (User Datagram Protocol) - used for information that requires no response,
such as streaming audio and video
6. ICMP (Internet Control Message Protocol) - used by a router to exchange the
information with other routers
7. SMTP (Simple Mail Transport Protocol) - used to send text-based information (e-
mail)
8. SNMP (Simple Network Management Protocol) - used to collect system
information from a remote computer
9. Telnet - used to perform commands on a remote computer
A company might set up only one or two machines to handle a specific protocol and ban
that protocol on all other machines.
Ports - Any server machine makes its services available to the Internet using
numbered ports, one for each service that is available on the server (see How Web
Servers Work for details). For example, if a server machine is running a Web (HTTP)
server and an FTP server, the Web server would typically be available on port 80, and the
FTP server would be available on port 21. A company might block port 21 access on all
machines but one inside the company.
Specific words and phrases - This can be anything. The firewall will sniff (search
through) each packet of information for an exact match of the text listed in the filter. For
example, you could instruct the firewall to block any packet with the word "X-rated" in
it. The key here is that it has to be an exact match. The "X-rated" filter would not catch
"X rated" (no hyphen). But you can include as many words, phrases and variations of
them as you need. Some operating systems come with a firewall built in. Otherwise, a
software firewall can be installed on the computer in your home that has an Internet
connection. This computer is considered a gateway because it provides the only point of
access between your home network and the Internet.
With a hardware firewall, the firewall unit itself is normally the gateway. A good
example is the Linksys Cable/DSL router. It has a built-in Ethernet card and hub.
10
11. Computers in your home network connect to the router, which in turn is connected to
either a cable or DSL modem. You configure the router via a Web-based interface that
you reach through the browser on your computer. You can then set any filters or
additional information.
Hardware firewalls are incredibly secure and not very expensive. Home versions that
include a router, firewall and Ethernet hub for broadband connections can be found for
well under $100.
What It Protects You From
There are many creative ways that unscrupulous people use to access or abuse
unprotected computers:
Remote login - When someone is able to connect to your computer and control it in
some form. This can range from being able to view or access your files to actually
running programs on your computer.
Application backdoors - Some programs have special features that allow for remote
access. Others contain bugs that provide a backdoor, or hidden access, that provides
some level of control of the program.
SMTP session hijacking - SMTP is the most common method of sending e-mail over
the Internet. By gaining access to a list of e-mail addresses, a person can send
unsolicited junk e-mail (spam) to thousands of users. This is done quite often by
redirecting the e-mail through the SMTP server of an unsuspecting host, making the
actual sender of the spam difficult to trace.
Operating system bugs - Like applications, some operating systems have backdoors.
Others provide remote access with insufficient security controls or have bugs that an
experienced hacker can take advantage of.
Denial of service - You have probably heard this phrase used in news reports on the
11
12. attacks on major Web sites. This type of attack is nearly impossible to counter. What
happens is that the hacker sends a request to the server to connect to it. When the server
responds with an acknowledgement and tries to establish a session, it cannot find the
system that made the request. By inundating a server with these unanswerable session
requests, a hacker causes the server to slow to a crawl or eventually crash.
E-mail bombs - An e-mail bomb is usually a personal attack. Someone sends you
the same e-mail hundreds or thousands of times until your e-mail system cannot
accept any more messages.
Macros - To simplify complicated procedures, many applications allow you to
create a script of commands that the application can run. This script is known as a
macro. Hackers have taken advantage of this to create their own macros that,
depending on the application, can destroy your data or crash your computer.
Viruses - Probably the most well-known threat is computer viruses. A virus is a
small program that can copy itself to other computers. This way it can spread quickly
from one system to the next. Viruses range from harmless messages to erasing all of
your data.
Spam - Typically harmless but always annoying, spam is the electronic equivalent
of junk mail. Spam can be dangerous though. Quite often it contains links to Web
sites. Be careful of clicking on these because you may accidentally accept a cookie
that provides a backdoor to your computer.
• Redirect bombs - Hackers can use ICMP to change (redirect) the path
information takes by sending it to a different router. This is one of the ways that a
denial of service attack is set up.
• Source routing - In most cases, the path a packet travels over the Internet (or any
other network) is determined by the routers along that path. But the source
providing the packet can arbitrarily specify the route that the packet should travel.
Hackers sometimes take advantage of this to make information appear to come
from a trusted source or even from inside the network! Most firewall products
disable source routing by default.
Some of the items in the list above are hard, if not impossible, to filter using a firewall.
While some firewalls offer virus protection, it is worth the investment to install anti-virus
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13. software on each computer. And, even though it is annoying, some spam is going to get
through your firewall as long as you accept e-mail.
The level of security you establish will determine how many of these threats can be
stopped by your firewall. The highest level of security would be to simply block
everything. Obviously that defeats the purpose of having an Internet connection. But a
common rule of thumb is to block everything, then begin to select what types of traffic
you will allow. You can also restrict traffic that travels through the firewall so that only
certain types of information, such as e-mail, can get through. This is a good rule for
businesses that have an experienced network administrator that understands what the
needs are and knows exactly what traffic to allow through. For most of us, it is probably
better to work with the defaults provided by the firewall developer unless there is a
specific reason to change it.
One of the best things about a firewall from a security standpoint is that it stops anyone
on the outside from logging onto a computer in your private network. While this is a big
deal for businesses, most home networks will probably not be threatened in this manner.
Still, putting a firewall in place provides some peace of mind.
Proxy Servers and DMZ
A function that is often combined with a firewall is a proxy server. The proxy
server is used to access Web pages by the other computers. When another computer
requests a Web page, it is retrieved by the proxy server and then sent to the
requesting computer. The net effect of this action is that the remote computer
hosting the Web page never comes into direct contact with anything on your home
network, other than the proxy server.
Proxy servers can also make your Internet access work more efficiently. If you
access a page on a Web site, it is cached (stored) on the proxy server. This means
that the next time you go back to that page, it normally doesn't have to load again
from the Web site. Instead it loads instantaneously from the proxy server.
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14. There are times that you may want remote users to have access to items on your
network. Some examples are:
• Web site
• Online business
• FTP download and upload area
In cases like this, you may want to create a DMZ (Demilitarized Zone). Although
this sounds pretty serious, it really is just an area that is outside the firewall. Think
of DMZ as the front yard of your house. It belongs to you and you may put some
things there, but you would put anything valuable inside the house where it can be
properly secured.
Setting up a DMZ is very easy. If you have multiple computers, you can choose to
simply place one of the computers between the Internet connection and the firewall.
Most of the software firewalls available will allow you to designate a directory on
the gateway computer as a DMZ.
Once you have a firewall in place, you should test it. A great way to do this is to go
to www.grc.com and try their free Shields Up! security test. You will get immediate
feedback on just how secure your system is!
Conclusion
A firewall is an information technology (IT) security device which is configured to
permit, deny or proxy data connections set and configured by the organization's security
policy. Firewalls can either be hardware and/or software based. A firewall is also called a
Border Protection Device (BPD) in certain military contexts were a firewall separates
networks by creating perimeter networks in a DMZ. In a BSD context they are also
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15. known as a packet filter. A firewall's function is analogous to firewalls in building
construction.
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