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Internet Security
Posted Date: 04 Feb 2008 Resource Type: Articles/Knowledge Sharing Category: General
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Posted By: jalaj Member Level: Diamond
Rating:  Points: 5
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The Cyber Crime Investigation Cell of Mumbai Police was inaugurated on 18th December 2000 and it is functioning under the overall guidance of Jt. Commissioner of Police (Crime), Addl. Commissioner of Police (Crime) and Dy. Commissioner of Police (Preventive)
Location:
Cyber Crime Investigation Cell is located at :
Cyber Crime Investigation cell,
Annex III, 1st floor, Office of the Commissioner of Police,
D.N.Road,
Mumbai - 400001
Email: officer@cybercellmu mbai.com
Tel:+91 - 022 - 22641261
Mumbai Police website: MumbaiPolice. org
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Internet Security
01. Background
Dr. Chandrasekhar Vasant Joshi is a Professor in Information Technology Management at IES Management College and Research Centre, Lotlikar Vidya Sankul, Opposite Lilawati Hospital, Bandra (West), Mumbai – 400 050. Dr. C. V. Joshi holds a BE degree in Electrical and Electronic Engineering and other post-graduate degrees in Computer Applications, Information Technology, Management Studies and Criminology and Environmental Law besides an M.Phil and a Ph.D in Educational Communication. Dr. C. V. Joshi has 18 years of computer software industry and academic experience and is also a student of Master of Population Sciences post-graduate degree course at International Institute of Population Sciences (Deemed University), Govandi Station Road, Mumbai – 400 088.
The present paper has primarily been compiled to include basic information on Internet Concepts and Security Issues for the benefit of police officers. A section on glossary of terms describes in simple words important terms related to Internet. The paper is a compilation of literature from different knowledge links available on Internet and it is felt that Mumbai Cyber Cell of Mumbai Police can make use of this compilation to gain an understanding into the basic concepts of internet security issues.
02. What is an Internet?
There is no single or generally agreed-upon answer to this question, because the internet is different for each of us.
Some of the definitions of Internet are as follows:
•It is a set of computers talking over fiber optics, phone lines, satellite links, and other media.
•It is a place where you can talk to your friends and family anywhere around the world.
•It is a place to get cool game demos.
•It is a place to do research for your thesis or a business presentation.
•It is a place where "crackers" and other shady characters lurk, waiting to wreak havoc.
•It is unlimited commercial opportunity.
•It is a worldwide support group for any problem or need.
•It is a gold mine of professionals in all fields sharing information about their work.
•It is hundreds of libraries and archives that will open to your fingertips
•It is the ultimate time-waster.
•It is the technology of the future that will help make our lives, and those of our children, brighter.
•An electronic network of computers, which includes nearly every university, government, and research facility in the world. Also included are many commercial sites. It started with four interconnected computers in 1969 and was known as ARPAnet.
•A network of computer networks which operates world-wide using a common set of communications protocols.
•A global network connecting millions of computers. As of 1999, the Internet has more than 200 million users worldwide, and that number is growing rapidly. More than 100 countries are linked into exchanges of data, news and opinions.
•A global network connecting millions of computers. More than 100 countries are linked into exchanges of data, news and opinions. Unlike online services, which are centrally controlled, the Internet is decentralized by design. Each Internet computer, called a host, is independent. Its operators can choose which Internet services to use and which local services to make available to the global Internet community. Remarkably, this anarchy by design works exceedingly well.
•The Internet, or simply the Net, is the publicly available worldwide system of interconnected computer networks that transmit data by packet switching using a standardized Internet Protocol (IP) and many other protocols. It is made up of thousands of smaller commercial, academic, domestic and government networks. It carries various information and services, such as electronic mail, online chat and the interlinked web pages and other documents of the World Wide Web.
All these answers are right, but none of them is complete. Today, the Internet is much more then it was a couple of decades ago, and in another five-six more years it will have grown so far that the cool toys we use today will be the ancient grandparents of the tools in use then.
03. What is World Wide Web (WWW)?
The World Wide Web (also called WWW, or W3 or simply the Web) is a tool that helps you to find and retrieve information, using links to other WWW pages. Web links are stored within the page itself and when you wish to "jump" to the next page that is linked, you select the "hotspot" or "anchor". This technique is sometimes called hypermedia or hypertext. We already have used hypertext in Windows based Help system. When we click on some underlined words, they lead us to a different topic. These underlined words are said to be in hypertext. The organization that maintains the standards that enable us to use the WWW is called the World Wide Web Consortium.
WWW clients on the Internet can display pages from any of the nearly 1 million Web servers. Each time you choose a link; WWW connects to the appropriate server, retrieves the next page wanted, and returns control to the local client. Once the document has been retrieved, the link is broken. This means that the server does not have to keep the link open while you read the document. WWW is thus an efficient method of finding and using information widely dispersed throughout the world.
World Wide Web is a system of Internet servers that support specially formatted documents. The documents are formatted in a language called HTML (Hyper Text Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means one can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web. Access to the Web is accomplished through a Web browser (e.g., Netscape Navigator, Microsoft Internet Explorer).
04. How does an Internet Work?
The thing that characterizes the Internet is how data is transferred from one computer to another. Did you ever wonder what magical things go on behind the scenes that results in a Web page being displayed on your screen seconds after you request it? How does the data get from one side of the world to the other?
Here’s what happens to a piece of data (e.g., a Web page) when it is transferred over the Internet:
•It is broken up into a whole lot of same-sized pieces (called packets).
•A header is added to each packet that explains where it came from, where it should end up and how it fits in with the rest of the packets.
•Each packet is sent from computer to computer until it finds its way to its destination. Each computer along the way decides where next to send the packet. This could depend on things like how busy the other computers are when the packet was received. The packets may not all take the same route.
•At the destination, the packets are examined. If there are any packets missing or damaged, a message is sent asking for those packets to be resent. This continues until all the packets have been received intact.
•The packets are reassembled into their original form.
Each computer connected up to the Internet has software called TCP/IP (Transmission Control Protocol/Internet Protocol) which is responsible for receiving, sending and checking packets. TCP/IP is the ‘glue’ of the Internet.
Say, for example, you are sending a message from Mumbai to New York ( USA ), to a server named nyork.org. The message will be broken up into packets of approximately 1500 bytes, and some may travel from VSNL here to the MCI router in the US, some may travel to Madras and then to the MCI router, and so forth. There is no predetermined path and individual packets of the same message may follow different paths. It all depends on the traffic at that node, at that moment of time.
As the packets reach nyork.org, they are put together as in the original message and delivered to the given address. In order to accomplish the task of messaging across a network, computers use a networking protocol. Taking the analogy of diplomacy, the relations and interactions between’s the representatives of different countries follow a set of rules laid down by tradition and treaty, which is called diplomatic protocol. Similarly, all computers wanting to talk to each other have to conform to a standard set of rules defined in the networking protocol
05. Domain Name System (DNS)
Initially, the success of Internet was not anticipated and hence no provision was made to include other countries. Now because of the overwhelming global success of the Internet, new top level domains are reserved, but not necessarily created, to correspond to individual countries. These national domain names follow an existing international official standard of two letter abbreviations for every country in the world.
Primary Domains " . " Countries
EDU fr
COM in
GOV us
MIL uk
ORG ca
An example of other countries represented with domains include: in India
au Australia
ca Canada
Fr France
UK The United Kingdom
Domains under "in" with net, ernet and CO
Let us discuss our top level domain "in" and its sub-domains. This top level domain is maintained by the National Center for Software Technology (NCST), as they were the first Internet node in India .
This scheme distributes the responsibility of keeping track of all the new additions of computers to the Internet. Within each category or hierarchy, this is done by the designated domain administrator or authority. For example, under the sub-domain "net" is the sub-domain "vsnl", which is responsible for all the hosts they may have e.g. giasbma, giasdl01, etc. VSNL comes under "net" because they are a network service provider. The service or host on which our Terminal accounts reside is "giasbm01", under "vsnl".
An example of a full Internet address under this arrangement is:
cvjoshi@ies. edu
Reading from left to right, this is the mail address for the user known as cvjoshi, on the server known as ies. This server is in the organizational sub-domain edu. This organization is located in the national domain "in" ( India ).
If the organization has large number of systems, then the organizational domain might also contain sub-domains, each of which contains a number of systems. This is often on a departmental or service basis. VSNL may in the future have thousands of systems connected to their network.
Source: http://www.cybercel lmumbai.com/ write-ups/ internet- security
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