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It is a global collection of networks, both big and small, that connect together in many different ways to form the single entity that we know as "the Internet." Who owns it? The Internet ernet Society, a non-profit group established in 1992, oversees the formation of the policies and protocols that define how we use and interact with the Internet.
The Internet is a gigantic collection of millions of computers, all linked together on a computer network. The network allows all of the computers to communicate with one another
When the Internet was in its infancy, you could only make connections by providing the IP (Internet Protocol) address of the computer you wanted to establish a link with. In 1983, the University of Wisconsin created the Doma main n Name me System m (DNS), which maps text names to IP addresses. This way you only need to remember www.villacollege.edu.mv, for example, instead of 202.1.x.y. The Domain Name System is a distributed database, but there are central name servers at the core of the system. Someone has to maintain these central name servers to avoid conflicts and duplication.
In 1993, the U.S. Department of Commerce, in conjunction with several public and private entities, created InterNI NIC to maintain a central database that contains all the registered domain names and the associated IP addresses in the U.S. (other countries maintain their own NICs (Network Information Centers). Network Solutions, a member of InterNIC, was chosen to administer and maintain the growing number of Internet domain names and IP addresses. This central database is copied to Top Level Domain (TLD) servers around the world and creates the primary routing tables used by every computer that connects to the Internet.
When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL "http://www.oum.edu.my" contains the domain name oum.edu.my. So does the e-mail address mymail@oum.edu.my. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "www.oum.edu.my" has the IP address 202.x.y.z. There are billions of DNS requests made every day.
Each host in the Internet is assigned to a specific and unique number for identification. This number is called the IP address of the specific host. This number is divided into 4 parts for improving the readability. The range of each number is between 0 and 255. ◦ E.g. 0.0.0.0 ◦ 255.255.255.255 For example, the host “www.villacollege.edu.mv” has its IP address of “202.1.x.y” These addresses are 32-bit numbers.
Every machine on the Internet has its own IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP address that is assigned by the ISP when you dial in. That IP address is unique for your session and may be different the next time you dial in. In this way, an ISP only needs one IP address for each modem it supports, rather than for every customer.
The COM, EDU and UK portions of the domain names are called the top-level domain or first-level domain. There are several hundred top-level domain names, including COM, EDU, GOV, MIL, NET, ORG and INT, as well as unique two-letter combinations for every country. Every name in the COM top-level domain must be unique, but there can be duplication across domains. For example, oum.com and oum.org are completely different machines. In the case of bbc.co.uk, it is a third-level domain. Up to 127 levels are possible, although more than four is rare. The left-most word, such as www or Encarta, is the host name. It specifies the name of a specific machine (with a specific IP address) in a domain.
Regi gisterin stering g a Domain ain Name The only way to register and start using a domain name is to use the services of a domain name registrar. The domain name industry is regulated and overseen by ICANN, the organisation that is responsible for certifying companies as domain name registrars. Only a domain name registrar is permitted to access and modify the master database of domain names maintained by InterNIC. ICANN-accredited registrars have the authority to assign domain names for the TLDs of .com, .biz. .info, .name, .net, and .org. ICANN does not, however, specifically accredit registrars to provide registration services for country code TLDs.
Wo World d Wi Wide We Web: World Wide Web is a system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web.
The Diff fference between the Interne net t and the World Wide Web: Many people use the terms Internet and World Wide Web (a.k.a. the Web) interchangeably, but in fact the two terms are not synonymous. The Internet and the Web are two separate but related things. The Internet is a massive network of networks, a networking infrastructure. The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet. The Internet, not the Web, is also used for e-mail, which relies on SMTP, Usenet news groups, instant messaging and FTP. So the Web is just a portion of the Internet, albeit a large portion, but the two terms are not synonymous and should not be confused.
E-mail is short for electronic mail, the transmission of messages over communications networks The messages can be notes entered from the keyboard or electronic files stored on disk. Sent messages are stored in electronic mailboxes until the recipient fetches them. All online services and Internet Service Providers (ISPs) offer e-mail, and most also support gateways so that you can exchange mail with users of other systems. Please read about SMTP, POP and IMAP
FTP is the protocol for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer.
In the computer industry, security refers to techniques for ensuring that data stored in a computer cannot be read or compromised by any individuals without authorisation. Most security measures involve data encryption and passwords. Data a encryp ryption ion is the translation of data into a form that is unintelligible without a deciphering mechanism. A passw sword ord is a secret word or phrase that gives a user access to a particular program or system.
Along with the convenience and easy access to information come new risks. Among them are the risks that valuable information will be lost, stolen, corrupted, or misused and that the computer systems will be corrupted. If information is recorded electronically and is available on networked computers, it is more vulnerable than if the same information is printed on paper and locked in a file cabinet.
Three basic security concepts important to information on the Internet are confidentiality, integrity, and availability. Concepts relating to the people who use that information are authentic nticat ation ion, authorisat sation ion, and nonrepudia pudiati tion on. When information is read or copied by someone not authorised to do so, the result is known as loss of f confi fidentia tiali lity ty. Information can be corrupted when it is available on an insecure network. When information is modified in unexpected ways, the result is known as loss of in f integrit ity.
Information can be erased or become inaccessible, resulting in loss ss of ava vail ilabil ability ity . This means that people who are authorized to get information cannot get what they need. When a user cannot get access to the network or specific services provided on the network, they experience a denial ial of servi vice ce . To make information available to those who need it and who can be trusted with it, organizations use authenti henticati cation on and authorization horization. Au Authent entication ication is proving that a user is whom he or she claims to be. Au Autho horization rization is the act of determining whether a particular user (or computer system) has the right to carry out a certain activity, such as reading a file or running a program.
The consequences of a break-in cover a broad range of possibilities: a minor loss of time in recovering from the problem, a decrease in productivity, a significant loss of money or staff-hours, a devastating loss of credibility or market opportunity, a business no longer able to compete, legal liability, and the loss of life.
A network security incident is any network- related activity with negative security implications. This usually means that the activity violates an explicit or implicit security policy. Incidents come in all shapes and sizes. They can come from anywhere on the Internet, although some attacks must be launched from specific systems or networks and some require access to special accounts.
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