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TCP/IP – The Entire Net

Runs On A Set of Rules

The entire Net runs on a set of rules. Rules defining a technology are known as protocols. They serve as a guiding factor for the technology to build upon. The Internet runs on the TCP/IP protocol. So to know the working of the Net, we must learn the basics first. So let's start.

What Is TCP/IP?

TCP/IP refers to two network protocols (or methods of data transport) used on the Internet. They are Transmission Control Protocol and Internet Protocol, respectively. These network protocols belong to a larger collection of protocols, or a protocol suite. These are collectively referred to as the TCP/IP suite. Protocols within the TCP/IP suite work together to provide data transport on the Internet. In other words, these protocols provide nearly all services available to today's Net surfer. Some of those services include

Transmission of electronic mail.

File transfers.

Usenet news delivery.

Access to the World Wide Web.

There are two classes of protocol within the TCP/IP suite. Those two classes are

The network-level protocol.

The application-level protocol.

Network-Level Protocols

Network-level protocols manage the discrete mechanics of data transfer. These protocols are typically invisible to the user and operate deep beneath the surface of the system. For example, the IP protocol provides packet delivery of the information sent between the user and remote machines. It does this based on a variety of information, most notably the IP address of the two machines. Based on this and other information, IP guarantees that the information will be routed to its intended destination. Throughout this process, IP interacts with other network-level protocols engaged in data transport. Short of using network utilities (perhaps a sniffer or other device that reads IP datagrams), the user will never see IP's work on the system.

Application-Level Protocols

Conversely, application-level protocols are visible to the user in some measure. For example, File Transfer Protocol (FTP) is visible to the user. The user requests a connection to another machine to transfer a file, the connection is established, and the transfer begins. During the transfer, a portion of the exchange between the user's machine and the remote machine is visible (primarily error messages and status reports on the transfer itself, for example, how many bytes of the file have been transferred at any given moment). For the moment, this explanation will suffice: TCP/IP refers to a collection of protocols that facilitate communication between machines over the Internet (or other networks running TCP/IP).

How Does TCP/IP Work?

TCP/IP operates through the use of a protocol stack. This stack is the sum total of all protocols necessary to complete a single transfer of data between two machines. (It is also the path that data takes to get out of one machine and into another.) The stack is broken into layers, five of which are of concern here. To grasp this layer concept, examine the figure.

The TCP/IP stack. After data has passed through the process illustrated in figure, it travels to its destination on another machine or network. There, the process is executed in reverse (the data first meets the physical layer and subsequently travels its way up the stack). Throughout this process, a complex system of error checking is employed both on the originating and destination machine. Each layer of the stack can send data to and receive data from its adjoining layer. Each layer is also associated with multiple protocols. At each tier of the stack, these protocols are hard at work, providing the user with various services.

Study of TCP/IP is a vast topic and naturally is impossible to cover in one lecture. So I will cover in depth in parts. Knowledge of TCP/IP is necessary to understand the concept of ports, sniffers, scanners and herein lies the fundamental concepts of Internet security. So follow the concepts clearly. Will see you next time.

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Hacking just Easy

Hacking

The series of article so far have tried to familiarize you with the fundamental concepts of security and the consequences resulting from security lapses. Today, I try to go into the restricted realms of computer security by discussing what is generally considered as a taboo by common people. Yes, I am talking about Hacking.

The term "hacking" in the 1980's became a buzzword in the media which was taken to be derogatory and which by misuse and overuse was attached to any form of socially non-acceptable computing activity outside of polite society. Within this context "hackers" were assumed to be the fringe society of the computing fraternity, mainly characterized as "youngsters" who did not know any better and who had obtained access to a technology with which they terrorized the world of communications and computing. To be tagged as a "hacker" was to portray a person as member of a less than acceptable group of near criminals whose activities were not be to be undertaken by the upright citizenry.

This was not the view of educated and knowledgeable computer or security professionals. This was the work of the media that created the existence of a hypothetical class of individuals who can then be branded as villains of the cyber era. This built on and the true meaning of the word and the intentions of this class was totally sidetracked.

Hackers are not criminals. They don't have intentions to damage or cause loss. They originated from the class of people who had an intrinsic thirst for knowledge. They wanted to stop at no point for gaining knowledge and letting the world benefit from their knowledge. Many historians will agree to the fact that knowledge always has been dangerous. People like Galileo, Pythagoras, etc had been banned because of the knowledge they possessed which was contradictory to popular belief. Same is the case with hackers. They possess that knowledge which others don't want them to possess.

Hackers are driven by curiosity. They have the urge to win. That makes them more aggressive, more intent and hence more dangerous, not to cyber society but to those narrow minded individuals.

Hacking and cracking are activities that generate intense public interest. Whenever anyone reads that some site was hacked into, some people get delighted, some don't. People who are delighted are those who don't have anything to do with such sites or with the Internet on the whole. Or they may be the persons who were responsible for the incident. Those who didn't excite were those people who are skeptical of this cyber world but still cannot live without it. Also the security world wakes up from sleep.

I am not a hacker. But I am also not a closed-minded person. I try give every individual a chance. Hence I don't treat hackers as criminals. I want you to think in that way too. Next time, we shall look into the psychology of hacking and difference between hackers and crackers.

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