The Internet ha become mission critical for many institutions today, including large and small companies, universities, and government agencies. Many individuals also rely on the Internet for many of their professional, social, and personal activities. But behind all this utility and excitement, there is a dark side, a side where "bad guys" attempt to wreak havoc in our daily lives by damaging our Internet-connected computers; violating our privacy, and rendering inoperable the Internet services on which we depend [Skoudis 2006].
The field of network security is about how the bad guys can attack computer networks and about how we, soon-to-be experts in computer networking, can defend networks against those attacks, or better yet, design new architectures that are immune to such attacks in the first place. Given the frequency and variety of existing attacks as well as the threat of new and more destructive future attacks, network security has become a central topic in the field of computer networking in recent years. One of the features of this fourth edition of this textbook is that it brings network security issues to the forefront.

We'll begin our foray into network security in this section, where we'll briefly describe some of the more prevalent and damaging attacks in today's Internet. Then, As we cover the various computer networking technologies.We'll consider the various, security-related issues associated with those technologies and protocols armed with our newly acquired expertise in computer networking and Internet protocols, we'll study in-depth how computer networks can be defended against attacks, or designed and operated to make such attacks impossible in the first place. Since we don't yet have expertise in computer networking and Internet protocols, we'll begin here by surveying some of today's more prevalent security-related problems. So we begin here by simply asking, what can go wrong? How are computer networks vulnerable? What are some of the more prevalent types of attacks today? The bad guys can put malware into your host via the Internet. We attach devices to the Internet because we want to receive/send data from/to the Internet. This includes all kinds of good stuff, including Web pages, e-mail messages, MP3s, telephone calls, live video, search engine results, and so on. But, unfortunately, along with all that good stuff comes malicious stuff-collectively known as malware-that can also enter and infect our devices.

Once malware infects our device it can do all kinds of devious things, including deleting our files; installing spy ware that collects our private information, such as social security num-hers, passwords, and keystrokes, and then sends this (over the Internet, of course!) back to the bad guys. Our compromised host may also be enrolled in a network of thousands of similarly compromised devices, collectively known as a botnet, which the bad guys control and leverage for spam e-mail distribution or distributed denial-of-service attacks(soon to be discussed) against targeted hosts. Much of the malware out there today is self-replicating: once it infects one host, from that host it seeks entry into other hosts over the Internet, and from the newly infected hosts, it seeks entry into yet more hosts. In this manner, self-replicating malware can spread exponentially fast. For example, the number of devices infected by the 2003 Saphire/Slammer worm doubled every 8.5 seconds in the first few minutes after its outbreak, infecting more than 90 percent of vulnerable hosts within 10 minutes [Moore 2003). Malware can spread in the form of a virus, a worm, or a Trojan horse [Skoudis 2004]. Viruses are malware that require some form of user interaction to infect the user's device. The classic example is an e-mail attachment containing malicious executable cods. If a user receives and opens such an attachment, the user inadvertently runs the malware on the device.

Before diving into software coding, you should have a broad architectural plan for your application. Keep in mind that an application's architecture is distinctly different from the network architecture. From the application developer's perspective, the network architecture is fixed and provides a specific set of services to applications. The application architecture, on the other hand, is designed by the application developer and dictates how the application is structured over the various end systems. In choosing the application architecture, an application developer will likely draw on one of the two predominant architectural paradigms used in modern network applications: the client-server architecture or the peer-to-peer (P2P) architecture.
In a client-server architecture, there is an always-on host, called the server, which services requests from many other hosts, called clients. The client hosts can be either sometimes-on or always-on. A classic example is the Web application for which an always-on Web server services requests from browsers running on client hosts. When a Web server receives a request for an object from a client host, it responds by sending the requested object to the client host. Note that with the client- server architecture, clients do not directly communicate with each other; for example, in the Web application, two browsers do not directly communicate. Another characteristic of the client-server architecture is that the server has a fixed, well- known address, called an IP address (which we'll discuss soon). Because the server has a fixed, well-known address, and because the server is always on, a client can always contact the server by sending a packet to the server's address. Some of the better-known applications with a client-server architecture include the Web, F1'R Telnet, and e-mail.

Often in a client-server application, a single server host is incapable of keeping up with all the requests from its clients. For example, a popular social-networking site can quickly become overwhelmed if it has only one server handling all of its requests. For this reason, a cluster of hosts-sometimes referred to as a server farm-is often used to create a powerful virtual server in client-server architectures. Application services that are based on the client-server architecture are often infrastructure intensive, since they require the service providers to purchase, install, and maintain server farms. Additionally, the service providers must pay recurring interconnection and bandwidth costs for sending an4 receiving data to and from the Internet. Popular services such as search engines (e.g., Google), Internet commerce (e.g., Amazon and e-Bay), Web- based v-mail (e.g, Yahoo Mail), social networking (e.g., MySpace and Facebook), and video sharing (e.g., YouTube) are infrastructure intensive and costly to provide.

In a P2P architecture, there is minimal (or no) reliance on always-on infrastructure servers. Instead the application exploits direct communication between pairs of intermittently connected hosts, called peers. The peers are not owned by the service provider, but are instead desktops and laptops controlled by users, with most of the peers residing in homes, universities, and offices. Because the peers communicate without passing through a dedicated server, the architecture is called peer-to-peer. Many of today's most popular and traffic-intensiye applications are based on P2P architectures. These applications include file distribution (e.g., BitTorrent), file searching/sharing (e.g., eMule and LimeWire), Intemet telephony (e.g., Skype), and IPTV (e.g., PPLive).

We saw earlier that end systems (user PCs, PDA's, Web servers, mail servers, and so on) connect into the Internet via an access network. Recall that the access network may be a wired or wireless local area network (for example, in a company, school, or library), a residential cable modem or DSL network, or a residential ISP (for example. AOL or MSN) that is reached via dial-up modem. But connecting end users and content providers into access networks -is only a small piece of solving the puzzle of connecting the hundreds of millions of end-systems and hundred of thousands of networks that make up the Internet. The Internet is a network of networks- understanding this phrase is the key to solving this puzzle. In the public Internet, access networks situated at the edge of the Internet are connected to the rest of the Internet through a tiered hierarchy of ISPs. Access ISPs (for example, residential cable and DSL networks, dial-up access networks such as AOL, wireless access networks, and company and university ISPs using LANs) are at the bottom of this hierarchy. At the very top of the hierarchy is a relatively small number of so-called tier-1 ISPs. In many ways, a tier-1 ISP is the same as any network-it has links and routers and is connected to other networks. In other ways, however, tier-I ISPs are special. Their link speeds are often 622 Mbps or higher, with the larger tier-I ISPs having links in the 2.5 to 10Gbps range; their routers must consequently be able to forward packets at extremely high rates. Tier-I ISPs are also characterized by being: * Directly connected to each of the other tier-1 ISPs * Connected to a large number of tier-2 lSPs and other customer networks * International in coverage Tier-l ISPs are also known as Internet backbone networks. These include Sprint, Verizon, (previously UUNet/WorldCom), AT&T, NT]', Level3, Qwest, and Cable & Wireless. Interestingly, no group officially sanctions tier-I status; as the saying goes-if you have to ask if you are a member of a group, you're-probably not. A tier-2 ISP typically has regional or national coverage, and (importantly) connects to only a few of the tier-I ISPs thus, in order to reach a large portion of the global Internet, a tier-2 ISP needs to route traffic through one of the tier-I ISPs to which it is connected. A tier-2 ISP is said to be a customer of the tier-I ISP to which it is connected, and the tier-1 ISP is said to be a provider to its customer. Many large companies and institutions connect their enterprise's network directly into a tier-I or tier-2 ISP, thus becoming a customer of that ISP. A provider ISP charges its customer ISP a fee, which typically depends on the transmission rate of the link connecting the two. A tier-2 network may also choose to connect directly to other tier-2 networks, in which case traffic can flow between the two tier-2 networks without having to pass through a tier-I network. Below the tier-2 ISPs are the lower-tier ISPs, which connect to the larger Internet via one or more tier-2 ISPs. At the bottom of the hierarchy are the access151's. Further complicating matters, some tier-I providers are also tier-2 providers (that is, vertically integrated), selling Internet access directly to end users and content providers, as well as to lower-tier ISPs. When two ISPs are directly connected to each other, they are said to peer with each other. An interesting study [Subramanian 2002] seeks to define the Internet's tiered structure more precisely by studying the Internet's topology in terms of customer- provider and peer-peer relationships.

Accompanying the current Internet revolution, the wireless revolution is also having a profound impact on the way people work and live. Today, more people in Europe have a mobile phone than a PC or a car. And the wireless trend is continuing with many analysts predicting that wireless (and often mobile) handheld devices -- such as mobile phones and PDAs-.will overtake wired computers as the dominant Internet access devices throughout the world. Today, there are two common types of wireless Internet access. In a wireless LAN, wireless users transmit/receive packets to/from a base station (also known as a wireless access point) within a radius of a few tens of meters. The base station is typically connected to the wired Internet and thus serves to connect wireless users to the wired network. In wide-area wireless access networks, packets are transmitted over the same wireless infrastructure used for cellular telephony, with the base station thus being managed by a telecommunications provider. This provides wireless access to users within a radius of tens of kilometers of the base station.
Wireless LANs, based on IEE 802.11 technology (also known as wireless Ethernet and WiFi), are currently enjoying widespread deployment in university departments, business offices, cafes, and homes. Many universities install IEEE 802.11 base stations across their campuses, allowing students to send and receive e-mail or surf the Web from anywhere on campus (for example, library, dorm room, classroom, or outdoor campus bench). In many cities, one can stand on a street corner and be within range of ten or twenty base stations (for a browse able global map of 802.11 base stations that have been discovered and logged on a Web site by people who take great enjoyment in doing such things, see [wiggle.net 20071). The most commonly deployed 802.11 technology.

Today many homes are combining broadband residential access (that is, cable modems or DSL) with inexpensive wireless LAN technology to create powerful home networks. This home network consists of a roaming laptop as well as a wired PC; a base station (the wireless access point), which communicates with the wireless PC; a cable modem, providing broadband access to the Internet; and a router, which interconnects the base station and the stationary PC With the cable modem. This network allows household members to have broadband access to the Internet, with one member roaming from the kitchen to the backyard to the bedrooms. The total fixed cost for such a network is less than $150 (including the cable/DSL modem). When you access the Internet through wireless LAN technology, you typically need to be within a few tens of meters of a base station. This is feasible for home access, coffee shop access, and, more generally, access within and around a building. But what if you are on the beach or in your car and you need Internet access? For such wide-area access, roaming Internet users make use of the cellular phone infrastructure, accessing base stations that are up to tens of kilometers away. Conceptually, this is similar to a home user with a dial-up connection to the Internet over a wired telephone line, except that now the cellular telephony infrastructure, rather than the wired telephony infrastructure, is used.

In delivering the best of services to respective recipients, IT based systems play a vital role for various companies. But then, these systems are often vulnerable to all types of changes. Thus, network configuration management is required.
Even though the configuration of your network devices experience constant change, they are very much under your control through the aid of a network configuration management. Furthermore, you will be able to find useful tools in making significant changes to the network. And if the recent changes you have made are proven to be unsuccessful, you can easily take them back and reuse the previous configuration.

In reality, handling the changes in your network is a very difficult task especially without a network configuration management. Changes are not documented automatically and therefore, you have to do it manually. In the case you forget to document all those changes, recalling them can be very frustrating.

All the computers that belong in a certain network are able to work in unison through the aid of a network configuration management. In most cases, constant changes are made on different devices in the system. And it becomes virtually hard to troubleshoot these certain changes when the time comes.

Network performance monitoring mainly focuses in understanding the details on network traffic and resource utilization. It is vital to perform this function with both the hardware and software of the network.

Like performing any other functions, network performance monitoring also requires specific tools. Windows 2000 provides one of the most commonly used tools. These tools are the Network Monitor and the System Monitor; tracing the resource utilization as well as the network throughput.

Windows 2000 Professional and the Windows 2000 Server are both needed in putting up the System Monitor while the Windows 2000 Server is the only system needed to set up the Network Monitor. Moreover, the Network Monitor supervises local traffic.

Other than aforementioned tools, network performance monitoring can also be done by other means. But then, it is important to bear in mind in choosing the best possible tools for the task.

For PC users, system upgrades like the soon-to-be-released Windows 7 are a cause for both excitement and anxiety. The excitement is for the new capabilities and performance improvements that Windows 7 promises. The anxiety comes from bitter experience. Many have tried Windows® upgrades in the past only to decide they liked the older version better. Then they discovered how hard it was to get their PC back to the way it had been prior to the upgrade.
Restoring a PC after an upgrade attempt can be difficult because the upgrade also replaces a host of software drivers with new code supporting the new Windows®. Removing the upgraded operating system does not always remove these new drivers, and re-installing the older Windows version will not necessarily re-install the drivers you had been using. As a result, your PC could end up with incompatible or obsolete drivers. Your PC might behave differently than it had before the update attempt, or it may even stop working. Incompatibility in key system drivers can leave the PC non-operational and your prospects for fixing the problem bleak.

To make sure your PC gets fully restored, you need to find out what drivers changed during the upgrade and subsequent regression, and identify which driver versions to re-install, a tedious and error-prone task.

Fortunately, there is a solution available called DriverAgent™(www.driveragent.com). This inexpensive and easy-to-use tool scans your PC to find all the drivers, and then searches an online database to determine if your drivers are all the right versions. It can also automatically download and install any drivers that need updating.

DriverAgent is especially useful for those planning to install a Windows upgrade because it offers a unique new feature - the Migration Wizard. This application makes upgrading or downgrading a much less risky proposition. It scans your hardware and builds a CD of all the drivers you will need for your target operating system.

By all accounts, Windows 7 seems like a winner; however, it never hurts to have a plan B if you need to downgrade. DriverAgent and its Migration Wizard make changing Windows versions so simple that you can do this upgrade fearlessly.

It has been said that the best defensive plan is an offensive one. The saying is true for any situation in which information is available to stop problems before they start, especially in the business world. In 2003, the Federal Trade Commission (FTC) announced it would be applying the same proactive principal to the widespread problem of identity theft and business fraud. By implementing mandatory standards of fraud security, the FTC's Red Flags Rule hopes to protect both businesses and consumers nationwide and fight back against hackers and identity thieves.
However, as with any attempt at mass standardization, the Red Flags Rule has been turbulent to introduce. The date by which all affected businesses are expected to comply has been moved twice since the rule was announced. Many businesses claim that the language of the rule has made them confused as to how to achieve compliance, or if their industry will be affected. The FTC has since increased its awareness programs, breaking Red Flags compliance down into four easy steps.

In this article, we will discuss the four steps of Red Flags Rule compliance, and how each is an opportunity for your business to take a proactive role in the fight against business fraud.

Step One: Identify Red Flags Every business industry has it own unique set of potential red flags, or indicators of potential business fraud. Before you can implement a successful program to detect and prevent red flags, it's essential to first identify suspicious activity unique to your corner of the business world. The FTC provides a series of categories to consider when building a list of relevant red flags, but also urges business owners in this stage to pay special attention to the details of the accounts they manage on a daily basis. What sort of accounts your business deals with-how they are accessed, managed and changed-will play an important role in helping you decide how you will focus on attempts at fraud on your business.

Step Two: Detecting Red Flags Relevant red flags may exist in two places: new customers and existing customers. It's important to have procedures in place to identify both new and current fraudsters in a way that is not disruptive to your daily business. Comprehensive identity verification and identity authentication systems, when paired with reliable data sources, can be essential tools in helping your business detect fraud. But, there is no universal detection system that will work for everyone. Depending on your industry and the sensitivity of your accounts, you may wish to pull consumer data from multiple sources or invest in an authentication or verification service that covers several different means of making sure your customers are who they say they are. It all depends on what works best for your business.

Step Three: Mitigate Red Flags If you encounter a red flag, it's important that your business and employees are aware of what steps must be taken to properly mitigate the threat and reduce the opportunity for it to happen again. The appropriate response may depend entirely on the situation, the nature of your business and the nature of your red flags detection program. The FTC offers a set of guidelines for dealing with red flags and fraud encounters, but as the business owner or operator, the situation is truly in your control. It's up to you to determine the best course of action to protect your business, your employees and your customers.

Step Four: Maintain Currency The methods with which identity thieves and fraudsters attack businesses change on a daily basis. It's essential for all Red Flags compliant businesses to keep their fraud prevention systems up to date with current industry knowledge in order to keep their prevention programs sharp. While a reliable data provider will stay up to date with consumer information, it's up to you and your business to identify which methods are most effective and which should be evaluated or updated for maximum impact on your unique operation.

The Red Flags Rule is simple in and of itself. By following these four easy steps to compliance, you'll be building a system that will effectively prepare you and your employees to prevent, mitigate and report fraud in your daily business. Your system will reach beyond the walls of your business and impact your business partners and customers alike. By being proactive, you'll be doing your part to keep transactions honest and customers confident in their decisions to bring their business to you.

Electronic Verification Systems, an industry leader with more than 10 years of data provision and fraud prevention services experience specializes in integrating identity verification and authentication procedures into established business security structures. We can help you detect and prevent identity fraud, making our solutions ideal for those seeking to become Red Flags compliant.