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NETWORK SECURITY CONCEPTS

Protection methods

1. Authorization - The process of an administrator granting rights and the process of checking user account permissions for access to resources are both referred to as authorization..
2. Authentication - Authentication is a process in which the credentials provided are compared to those on file in a database of authorized users’ information on a local operating system or within an authentication server. If the credentials match, the process is completed and the user is granted authorization for access.
3. Encryption – Encryption is the conversion of electronic data into another form, called cipher text, which cannot be easily understood by anyone except authorized parties. The primary purpose of encryption is to protect the confidentiality of digital data stored on computer systems or transmitted via the Internet or other computer networks.
4. Biometric System - involves unique aspect of a person's body such as Finger-prints, retinal patterns etc to establish his/her Identity.
5. Firewall - A system designed to prevent unauthorized access to or from a private network is called firewall. it can be implemented in both hardware and software or combination or both.

There are several types of firewall techniques-

* Packet filter- accepts or rejects of packets based on user defined rules.
* Application gateway- security mechanism to specific application like FTP and Telnet servers.
* Circuit level gateway - applies security mechanism when a connection is established.
* Proxy Server - Intercepts all messages entering and leaving the network.

6. Cookies - Cookies are messages that a web server transmits to a web browser so that the web server can keep track of the user’s activity on a specific web site. Cookies have few parameters name, value, expiration date etc
7. Web 2.0 describes World Wide Web sites that emphasize user-generated content, usability, and interoperability. The term was popularized by Tim O'Reilly and Dale Dougherty at the O'Reilly Media Web 2.0 Conference in late 2004. Examples of Web 2.0 include social networking sites, blogs etc.

Hackers and crackers -

A hacker is a person intensely interested in the secret and complex workings of any computer operating system. Hackers are most often programmers. As such, hackers obtain advanced knowledge of operating systems and programming languages. They might discover holes within systems and the reasons for such holes. Hackers constantly seek further knowledge, freely share what they have discovered, and never intentionally damage data.
A cracker is one who breaks into or otherwise violates the system integrity of remote machines with malicious intent. Having gained unauthorized access, crackers destroy vital data, deny legitimate users service, or cause problems for their targets. Crackers can easily be identified because their actions are malicious.

Cyber Law -

It is a generic term, which refers to all the legal and regulatory aspects of internet and the World Wide Web.


WEB SERVERS

WWW (WORLD WIDE WEB)

It is a small part of Internet. It is a kind of Application of internet. It is a set of protocols that allows us to access any document on the Net through a naming system based on URLS. Internet was mainly used for obtaining textual information. But post-WWW the internet popularity grew tremendously because of graphic intensive nature of www.

Attributes of WWW

(i) User friendly- www resources can be easily used with the help of browser.
(ii) Multimedia documents- A web page may have graphic, audio, video, and animation etc at a time.
(iii) Hypertext and hyperlinks- the dynamic links which can move towards another web page is hyperlink.
(iv) Interactive - www with its pages support and enable interactivity between users and servers.
(v) frame-display of more than one section on single web page.

Web server-

It is a WWW server that responds to the requests made by web browsers. e.g. : Apache, IIS, PWS(Personal web server for Windows 98).

Web browser-

It is a WWW client that navigates through the World Wide Web and displays web pages. E.g.: FireFox Navigator, Internet Explorer etc.

Web sites-

A location on a net server where different web pages are linked together by dynamic links is called a web site. Each web site has a unique address called URL.

Web page -

A document that can be viewed in a web browser and residing on a web site is a web page.

Home page-

a web page that is the starting page and acts as an indexed page is home page.

Web portal -

A Web portal or public portal refers to a Web site or service that offers a broad array of resources and services, such as e-mail, forums, search engines, and online shopping malls.. for e.g. www.yahoo.com,www.rediff.com

Domain name-

An internet address which is a character based is called a Domain name. Some popular domain names are:- google.com,microsoft.com etc. Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. Some most common domain suffix are com, edu, gov, mil, net, org, and co. Some domain name suffix are location based also. For e.g. au for Australia, ca for Canada, in for India etc.

URL-

A URL (uniform resource locator) that specifies the distinct address for each resource on the internet.

Web hosting -

means hosting web server application on a computer system through which electronic content on the internet is readily available to any web browser client.

HTML -

It stands for Hyper Text Markup Language that facilitates to write web document that can be interpreted by any web browser. It provide certain tags that are interpreted by the browser how to display and act with the text, graphics etc. tags are specified in <>. body is the tag with bgcolor attributes.

XML (eXtensible Markup Language)

Extensible Markup Language (XML) is used to describe data. The XML standard is a flexible way to create information formats and electronically share structured data via the public Internet, as well as via corporate networks. The main difference between HTML and XML is, HTML is all about presentation and XML is used to describe data.

DHTML-

It stands for Dynamic Hyper Text Markup Language. DHTML refers to Web content that changes each time it is viewed. For example, the same URL could result in a different page depending on any number of parameters, such as: *geographic location *time of the day *previous pages viewed by the user *profile of the reader

WEB SCRIPTING –

The process of creating and embedding scripts in a web page is known as web-scripting.

SCRIPT:

A Script is a list of commands embedded in a web page. Scripts are interpreted and executed by a certain program or scripting –engine.

Types of Scripts:

1. Client Side Script: It generally refers to the class of computer programs on the web that are executed client-side, by the user's web browser, instead of server-side (on the web server). Some popular client-side scripting languages are VBScript, JavaScript, PHP (Hyper Text Preprocessor).
2. Server-Side Scripts: Server-side scripting enables the completion or carrying out a task at the server-end and then sending the result to the client –end.
Some popular server-side Scripting Languages are PHP, Perl, ASP (Active Server Pages), JSP (Java Server Pages) etc.

OPEN SOURCE TERMINOLOGIES

TERMINOLOGY & DEFINITIONS:

• Free Software: The S/W’s is freely accessible and can be freely used, changed, improved, copied and distributed by all. It may be free of cost or may be some amount is to be paid.
• Open Source Software: S/w whose source code is available to the customer and it can be modified and redistributed without any limitation .OSS may come free of cost or nominal charges has to pay nominal charges (Support of S/W and development of S/W).
• FLOSS (Free Libre and Open Source Software) : S/w which is free as well as open source S/W. ( Free S/W + Open Source S/W).
• GNU (GNU’s Not Unix) : GNU project emphasize on the freedom and its objective is to create a system compatible to UNIX but not identical with it.
• FSF (Free Software Foundation) : FSF is a non –profit organization created for the purpose of the free s/w movement. Organization funded many s/w developers to write free software.
• OSI (Open Source Initiative) : Open source software organization dedicated to cause of promoting open source software it specified the criteria of OSS and its source code is not freely available.
• W3C(World Wide Web Consortium) : W3C is responsible for producing the software standards for World Wide Web.
• Proprietary Software: Proprietary Software is the s/w that is neither open nor freely available, normally the source code of the Proprietary Software is not available. Some examples are MS Office, Adobe Photoshop.
• Freeware: Freeware are the software freely available , which permit redistribution but not modification (and their source code is not available). Freeware is distributed in Binary Form (ready to run) without any licensing fees. Some examples are Skype, Adobe reader etc.
• Shareware: Shareware is software that is distributed free on a trial basis with the understanding that the user may need or want to pay for it later. Some software developers offer a shareware version of their program with a built-in expiration date (after 30 days, the user can no longer get access to the program). Some examples are Antivirus software such as Kaspersky, K7 etc.
• Localization: localization refers to the adaptation of language, content and design to reflect local cultural sensitivities .e.g. Software Localization: where messages that a program presents to the user need to be translated into various languages.
• Internationalization: Internationalization is the design and development of a product, application or document content that enables easy localization for target audiences that vary in culture, region, or language.

OPEN SOURCE / FREE SOFTWARE

Linux : Linux is a famous computer operating system . popular Linux server set of program –LAMP(Linux, Apache, MySQL, PHP)
Mozilla : Mozilla is a free internet software that includes
• a web browser
• an email client
• an HTML editor
• IRC client
Apache server: Apache web server is an open source web server available for many platforms such as Linux, and Microsoft Windows etc.
• Apache Web server is maintained by open community of developers of Apache software foundation.
MYSQL : MYSQL is one of the most popular open source database system. Features of MYSQL :
• Multithreading
• Multi –User
• SQL Relational Database Server
• Works at many different platform
PostgreSQL : Postgres SQL is a free software object relational database server . PostgreSQL can be downloaded from www.postgresql.org.
Pango : Pango is a library for laying out and rendering of text, with an emphasis on internationalization. Pango can be used anywhere that text layout is needed, though most of the work on Pango so far has been done in the context of the GTK+ widget toolkit..
OpenOffice : OpenOffice is an office applications suite. It is intended to compatible and directly complete with Microsoft office.
OOo Version 1.1 includes:
• Writer (word processor)
• Calc (spreadsheet)
• Draw(graphics program)
• Presentation
Tomcat: Tomcat functions as a servlet container. Tomcat implements the servlet and the Java Server Pages .Tomcat comes with the jasper compiler that complies JSPs into servlets.
PHP(Hypertext Preprocessor) : PHP is a widely used open source programming language for server side application and developing web content.
Python: Python is an interactive programming language originally as scripting language for Amoeba OS capable of making system calls.




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