This computer network and computer network security site aims to provide book reviews and free ebooks on network security, tcp ip protocols, internetworking, osi model, socket programming, internet protocols,ipv6, voice over internet protocol, port authority, port forwarding, wireless networking, home networking, computer networking,client server computing, client server software etc.

Communication Networks

By Sharam Hekmat
This book is concerned with post-computer communication networks and two of its important streams: data communication and telecommunication. Data communication refers to the communication between digital computers, facilitated by computer networks. Telecommunication refers to the primarily human-to-human communication facilitated by the global telephone system. The differences between these two streams are mainly due to historical reasons. Telecommunication is increasingly relying on digital computer technology, and data communication is relying more than ever on telecommunication networks. The two streams are rapidly converging.
Newcomers to this field are often bewildered by the substantial wealth of information already published on the subject. This book is aimed at this group of people. It provides a broad coverage of the key concepts, techniques, and terminology, so as to prepare readers for more advanced discussions. In-depth discussions of technically-involved topics are intentionally avoided in favor of more general concepts. No previous knowledge of networks or programming is assumed.
The structure of the book is as follows. Chapter 1 introduces computer networks and explains some of their elementary concepts. It also introduces the OSI reference model, upon which later chapters are based. Each of Chapters 2-8 describes one of the seven layers of the OSI model in the context of wide area data networks. Chapter 9 looks at local area networks and their applications. Chapter 10 provides an introduction to telecommunication. Chapter 11 builds on earlier chapters by examining ISDN as the merging point of data and voice networks. Chapter 12 looks at the ATM technology and the potential applications that it can support.

Introduction to Data Communications

by Eugene Blanchard
Data Communications is the transfer of data or information between a source and a receiver. The source transmits the data and the receiver receives it. The actual generation of the information is not part of Data Communications nor is the resulting action of the information at the receiver. Data Communication is interested in the transfer of data, the method of transfer and the preservation of the data during the transfer process.
In Local Area Networks, we are interested in "connectivity", connecting computers together to share resources. Even though the computers can have different disk operating systems, languages, cabling and locations, they still can communicate to one another and share resources.
The purpose of Data Communications is to provide the rules and regulations that allow computers with different disk operating systems, languages, cabling and locations to share resources. The rules and regulations are called protocols and standards in Data Communications.....
What is a Network? A network can consist of two computers connected together on a desk or it can consist of many Local Area Networks (LANs) connected together to form a Wide Area Network (WAN) across a continent.
The key is that 2 or more computers are connected together by a communication medium and they are sharing resources. The resources can be files, printers, hard-drives or cpu number crunching power.....

Building Internet Firewalls Second Edition

By Elizabeth D. Zwicky, Simon Cooper and D. Brent Chapman
Part I, "Network Security", explores the problem of Internet security and focuses on firewalls as part of an effective strategy to address that problem.
  • Chapter 1, "Why Internet Firewalls?", introduces the major risks associated with using the Internet today; discusses what to protect, and what to protect against; discusses various security models; and introduces firewalls in the context of what they can and can't do for your site's security.
  • Chapter 2, "Internet Services", outlines the services users want and need from the Internet, and summarizes the security problems posed by those services.
  • Chapter 3, "Security Strategies", outlines the basic security principles an organization needs to understand before it adopts a security policy and invests in specific security mechanisms.

Part II, "Building Firewalls", describes how to build firewalls.

  • Chapter 4, "Packets and Protocols ", describes the basic network concepts firewalls work with.
  • Chapter 5, "Firewall Technologies", explains the terms and technologies used in building firewalls.
  • Chapter 6, "Firewall Architectures", describes the major architectures used in constructing firewalls, and the situations they are best suited to.
  • Chapter 7, "Firewall Design", presents the process of designing a firewall.
  • Chapter 8, "Packet Filtering" describes how packet filtering systems work, and discusses what you can and can't accomplish with them in building a firewall.
  • Chapter 9, "Proxy Systems", describes how proxy clients and servers work, and how to use these systems in building a firewall.
  • Chapter 10, "Bastion Hosts", presents a general overview of the process of designing and building the bastion hosts used in many firewall configurations.
  • Chapter 11, "Unix and Linux Bastion Hosts", presents the details of designing and building a Unix or Linux bastion host.
  • Chapter 12, "Windows NT and Windows 2000 Bastion Hosts ", presents the details of designing and building a Windows NT bastion host.

Part III, "Internet Services", describes how to configure services in the firewall environment.

  • Chapter 13, "Internet Services and Firewalls", describes the general issues involved in selecting and configuring services in the firewall environment.
  • Chapter 14, "Intermediary Protocols", discusses basic protocols that are used by multiple services.
  • Chapter 15, "The World Wide Web", discusses the Web and related services.
  • Chapter 16, "Electronic Mail and News", discusses services used for transferring electronic mail and Usenet news.
  • Chapter 17, "File Transfer, File Sharing, and Printing", discusses the services used for moving files from one place to another.
  • Chapter 18, "Remote Access to Hosts", discusses services that allow you to use one computer from another computer.
  • Chapter 19, "Real-Time Conferencing Services", discusses services that allow people to interact with each other online.
  • Chapter 20, "Naming and Directory Services", discusses the services used to distribute information about hosts and users.
  • Chapter 21, "Authentication and Auditing Services", discusses services used to identify users before they get access to resources, to keep track of what sort of access they should have, and to keep records of who accessed what and when.
  • Chapter 22, "Administrative Services", discusses other services used to administer machines and networks.
  • Chapter 23, "Databases and Games", discusses the remaining two major classes of popular Internet services, databases and games.
  • Chapter 24, "Two Sample Firewalls", presents two sample configurations for basic firewalls.

Part IV, "Keeping Your Site Secure", describes how to establish a security policy for your site, maintain your firewall, and handle the security problems that may occur with even the most effective firewalls.

  • Chapter 25, "Security Policies", discusses the importance of having a clear and well-understood security policy for your site, and what that policy should and should not contain. It also discusses ways of getting management and users to accept the policy.
  • Chapter 26, "Maintaining Firewalls", describes how to maintain security at your firewall over time and how to keep yourself aware of new Internet security threats and technologies.
  • Chapter 27, "Responding to Security Incidents", describes what to do when a break-in occurs, or when you suspect that your security is being breached.

Part V, "Appendixes", consists of the following summary appendixes:

  • Appendix A, "Resources", contains a list of places you can go for further information and help with Internet security: World Wide Web pages, FTP sites, mailing lists, newsgroups, response teams, books, papers, and conferences.
  • Appendix B, "Tools", summarizes the best freely available firewall tools and how to get them.
  • Appendix C, "Cryptography", contains background information on cryptography that is useful to anyone trying to decrypt the marketing materials for security products.