Internet concept

 

Internet & email

Internet: 

      Yeah, everybody’s talking about Internet these days. But what is it really, how does it work? How do we access it? Etc… these all are the questions arising in our mind. Let’s not wait for long time. Let’s move for this.

                    Definition:-                         

Internet is a web of networks i.e. interconnection of large number of computers throughout the world. The computers are connected (wired or wireless via satellite) in such a way that anybody from anywhere can access anything/information. It is the largest network in the world just like a communication service provided by different companies. It is not limited in a room or a building or just an office. But by just sitting on a chair in one corner we can access the information, we can go for meeting or conference or shopping etc. while accessing the information from remote computers, it seems that a user is retrieving information from inside the cpu/hard disk. It does not take more time to fetch the information. While getting the data/packets, all the computers use a common rule called protocol (TCP/IP). Without this, even a single computer can not communicate. The Internet can be considered as a super highway with multi lanes and with high traffic of data without letting it jam.

                             Internet, which stands for “International Network” was coined first time by Arpanet as well as DARPAnet, lead by scientist Dr. J.C.R. Licklider (Joseph Carry Robnett) a U.S. Department of Defense project to create a nationwide computer network that would continue to function in 1962 AD. Later on gradual development went on by other different scientists. Firstly, it was tested to share research papers by different scientist and from different location throughout the universities but later (about two decades) different other organizations used for multi tasks.

Uses of Internet:-

             It has many advantages and can not be mentioned by just writing here. But to know how it works and where it is used, let’s see some.

File sharing/transferring:-

A file can be put on a "Shared Location" or onto a File Server for instant use by colleagues does not matter what is a size of file and how many will use it. Mirror servers and peer-to-peer networks can be used to ease the load of data transfer.

Internet banking:-

We know that almost all banks now-a-days are using this technology for its customers as an extra facility. Internet Banking/Online Banking allows bank customers to do financial transactions on a website operated by the banks. The customers can do almost any kind of transaction on the secured websites. They can check their account balance, transfer funds, pay bills, etc. but security is a major issue for this.

Relay of information/communication:-

The biggest advantage of that internet is offering of information. The internet and the World Wide Web has made it easy for anyone to access information, and it can be of any type, as the internet is a sea of information. The internet and the World Wide Web have made it easy for anyone to access information, and it can be of any type. Any kind of information on any topic is available on the Internet. As well as, it can be greatly used for communication purpose for any distance.

Dating/Personals: 

People are connecting with others through internet and finding their life partners. Internet not only helps to find the right person but also to continue the relationship.

Job Search:

 If we want to work and want to show our skill then Internet is right place. On this we can work in any flexible time and we can make money. Internet makes life easy for both employers and job seekers as there are plenty of job sites which connect employers and job seekers.

Remote access:-

Suppose, if we want to use a computer which is not near to us, is there a solution? Yeah, there is. By using Internet and networking. Computer users can easily connect to other computers and information stores around the world using the internet. The access can be done with or without security, authentication and encryption, depending on the needs. 

Online education:

Do not want to go any where! Want to get a good degree by staying at home? Yah, the Internet has made this very easy and simple. We can learn on computer by using Internet and distance mode education where the different professors/trainers teach just like they were in same class room. Now-a-days it is getting more popularity.

Internet radio:

By using Internet we can listen the radio, we can watch TVs of any country and from anywhere. It uses stream of bits and software transmitted over protocol.

Disadvantages:

Theft of Personal Information

 If you use the Internet for online banking, social networking or other services, you may risk a theft to your personal information such as name, address, credit card number etc. Unscrupulous people can access this information through unsecured connections or by planting software and then use your personal details for their benefit. Needless to say, this may land you in serious trouble. 

Spamming 

Spamming refers to sending unwanted emails in bulk, which provide no purpose and needlessly obstruct the entire system. Such illegal activities can be very frustrating for you as it makes your Internet slower and less reliable.

Virus Threat:

Internet users are often plagued by virus attacks on their systems. Virus programs are inconspicuous and may get activated if you click a seemingly harmless link. Computers connected to Internet are very prone to targeted virus attacks and may end up crashing. 

Pornography

Pornography is perhaps the biggest disadvantage of Internet. Internet allows you to access and download millions of pornographic photos, videos and other X-rated stuff. Such unrestricted access to porn can be detrimental for children and teenagers. It can even play havoc in marital and social lives of adults.

 Social Disconnect

Thanks to Internet, people now only meet on social networks. More and more people are getting engulfed in virtual world and drifting apart from their friends and family. Even children prefer to play online games rather than going out and mingling with other kids. This may hamper a healthy social development in children. 

Privacy:

There are many websites which we visit very frequently. In some sites we enter our personal information. This entry lets our privacy to be public which should not be. Mainly in social sites; it has been a great problem for all viewers or companies or customers. We know that the privacy should be confidential which they are not able to maintain.

Terminologies:-

Protocols:

When computers communicate with each other, there needs to be a common set of rules and instructions that each computer follows. A specific set of communication rules is called a protocol. Because of the many ways computers can communicate with each other, there are many different protocols -- too many for the average person to remember. Some examples of these different protocols include POP, TCP/IP, HTTP, and FTP. Let’s see about some of them.

             TCP/IP:

                     We know that protocol is that rule which lets the computers to have communication. The protocol provides an exact format about packet of bits to be sent and received. It also provides a condition under which data should be sent and with what message. This protocol is used or exits in operating system. It has two protocols namely TCP, called Transmission control Protocol and IP called Internet protocol. Here, TCP is that protocol which handles the lost datagrams (packets with destination address) and delivery of a complete datagram.

             Whereas IP is another protocol used for transferring the packets over an established connection. It knows how to form a packet and how a router transfers that packet over different computers.

             HTTP:

              The most common service given by Internet is WWW. Under www, there can be several sites having thousands of pages. To control those pages and their movement http is used. This protocol makes web workable. When we type any URL, our computer sends a request to server via this protocol. This protocol is responsible to transfer files having audios, videos, texts etc to all other computers instantly.

             FTP:

           Another kind of protocol used to transfer files or exchange files from our computer to internet and vice-versa. Mostly it is used to transfer web-pages to web-server and to host from there.

 

TCP/IP is TCP and IP working together.

TCP takes care of the communication between your application software (i.e. your browser) and your network software.

IP takes care of the communication with other computers.

TCP is responsible for breaking data down into IP packets before they are sent, and for assembling the packets when they arrive.

IP is responsible for sending the packets to the correct destination.

Web-browser:-

                     Accessing the Internet is not so easy if we do not have software which can recognize the html page and can convert into readable format for the users. On Internet, we can see millions of html pages. Obviously, all the pages are designed by using HTML tags. So to recognize its tag and convert into some like English language or readable format for the users, we need some kind of browser software. This software translates the page after downloading in computers memory into readable format.

                                                             The primary purpose of a web browser like Chrome, IE, Safari etc is to bring information resources to the user. This process begins when the user inputs a Uniform Resource Locator (URL), for example http://en.wikipedia.org/, into the browser. The prefix of the URL, the Uniform Resource Identifier or URI, determines how the URL will be interpreted. The most commonly used kind of URI starts with http: and identifies a resource to be retrieved over the Hypertext Transfer Protocol (HTTP). Many browsers also support a variety of other prefixes, such as https: for HTTPS, ftp: for the File Transfer Protocol, and file: for local files. Prefixes that the web browser cannot directly handle are often handed off to another application entirely. For example, mailto: URIs are usually passed to the user's default e-mail application, and news: URIs are passed to the user's default newsgroup reader.

 

Web-site:-

It’s a collection of files and related resources accessible through the World Wide Web and organized under a particular domain name. Typical files found at a Web site are HTML documents with their associated graphic image files (GIF, JPEG, etc.), scripted programs (in Perl, CGI, Java, etc.), and similar resources. The site's files are usually accessed through hypertext or hyperlinks embedded in other files. A Web site may consist of a single HTML file, or it may comprise hundreds or thousands of related files. A Web site's usual starting point or opening page, called a home page or index or default, usually functions as a table of contents or index, with links to other sections of the site. Web sites are hosted on one or more Web servers, which transfer files to client computers or other servers that request them using the HTTP protocol. Although the term "site" implies a single physical location, the files and resources of a Web site may actually be spread among several servers in different geographic locations. The particular file desired by a client is specified by a URL that is either typed into a browser or accessed by selecting a hyperlink.

 

Web-page:-

                  A single page of web-site is called web-page. This page exists on web server while hosting. Users mostly feed-up some information by using html tags for commercial or public interest purpose. All the web-pages are interlinked to each other with different information. We can see data like text, audio, video, animation, images embedded over there. To make page effective, some more scripting languages are used like php, asp or jsp. We can access page by using http. Web pages may consist of files of static text and other content stored within the web server's file system (static web pages), or may be constructed by server-side software when they are requested (dynamic web pages). Client-side scripting can make web pages more responsive to user input once on the client browser.

Web-server:  

     It‘s a powerful computer located at very far distance. It is used to store huge amount of web-sites for different companies for any kind of jobs and to host them. Whenever a client computer gives a request for a page, if it has then it transfers to that client computer with the help of protocols. To host and to store web-pages, it uses a powerful operating system like Unix, Linux with different web-server softwares like Apache, IIS, Tomcat etc. the web server has high processing capability and can process many of requests at same time without any alteration and problem. Besides web-page, it also provides some other facilities like mail servicing, ftp servicing, intranet service server side programming (CGI), security, Firewall, search engine etc. while choosing a web-server, one should know the working capability, speed , workload of that server.

 

URL:- 

      We know that Internet is full of thousand of millions of pages. All the web-pages have unique name or an address at which they contain related information called domain name. this location is called URL. By using this we can search, download, view the content part of site. It is an address which contains several parts. To be clear, let’s take an example. A URL is one type of Uniform Resource Identifier (URI); the generic term for all types of names and addresses that refer to objects on the World Wide Web.

http://www.ekantipur.com, here in this URL, first part is called protocol which transfers the web –page according to need or demand and somewhere searches and fetches. www is a world wide web service of Internet. Ekantipur is domain name of organization “kantipur”. This domain name can never be same. At last, we can see com means the site is commercially launched on internet. Sometimes it is also called top level domain. It it contains .np then we can understand that this is low level domain or country level domain which mostly carries two characters.

 

Browser:

An application or software which is used to retrieve, display and interact with web-server for the contents contained in web-page so far requested by clients. Browser acts as a mediator between a client and web server. When a client gives a request by typing a URL in address bar and hit that then browser starts process. Suppose, if you type http://google.com then browser comes to know that user is trying to reach or load Google domain with protocol http. The browser knows better how to interpret and fetch the written in certain language with some other scripting language like php, asp cgi etc and how do display properly on screen.

                                               The browsers available now-a-days are fully-functional software suites that can interpret and offer plug-ins which extend the capabilities of a browser so it can display multimedia information (including sound and video), or the browser can be used to perform tasks such as videoconferencing, to design web pages or add anti-phishing filters and other security features to the browser. Many examples we have, google chrome, Mozilla opera etc.

DNS:

DNS which stands for Domain Name System or Domain Name Service/Server is used to translate the entered domain name in address bar by user into an IP. Like, if we enter http://www.google.com then the DNS translates into corresponding IP which is a unique protocol for all servers /computers on Internet. We use alphabetical letters as domain because it is easy to remember but our internet is based on protocol so the domain name is translated into corresponding numbers. Having translated, the server searches for that protocol in it first; whether that is available or not, if that is available; it sends the packets to client. If not, then it communicates with top level (other server) server called root server. As it gets required IP, immediately it sends to client.  For this, server uses software called DNS resolver. All the DNS servers are arranged in some like hierarchical order i.e. from top level to bottom level. The server goes on searching from bottom to top (root level) until it gets the IP. Totally we have 13 root servers in world in different countries. These all are used to manage all domains throughout the world. Left all others are temporary server.

Search engine:

                   Thousands of sites on internet! But suppose, if we want to search a particular data or particular site, then any way there? Yeah, there is. There is some software or web-sites which are designed specially to search a word or site or image etc. this type of site /program is called Search Engine. While searching we can use different word, number or operator or image etc. the search engine sends spider/s (a program used to feed pages to search engine, it crawls over pages) to fetch as many as documents possible. Besides spider, it also uses Indexer which Indexes the pages after reading. The search engine uses some special algorithms for searching purpose. We have many like Google, Yahoo, alta-Vista etc. The alta-vista uses many spiders in parallel way. Apart from search engine, we have Meta search engine which is used to search by using many search engine and to display combined result. Like mamma.com, dogpile.com etc

 

Messenger services:- 

                  One of the great advantages for the users to have conversation in real time or without delay is messenger service. There are varieties of software by different companies like Yahoo, Microsoft, Rediffbol. By using these we can easily start chatting. The software automatically shows the friends who are online or offline and instantly we can start chat session. Firstly it was only text based but, now it has been providing voice based as well as video based chatting. We can chat with a person or we can make a group and then can have chat or discus on a subject.

                                                                             Besides this chatting, we have other kinds of messaging service which is used in networking environment by super user to send message to its customers or clients. Mostly in cyber café or a university where we have to handle many users at same time, the users are handled /monitored by using this kind of software. Like what are they doing? What site they are visiting? Etc.

 

E-mail:-

       A mailing facility provided by an ISP or web-site by using which we can send or receive mails in no time and electronically. It does not take more time to send message or files to a user living in any corner of the world. At one time we can send mails to many. Apart from mail, we can also send large files, audios, videos, images. While sending mails if we unknowingly enter wrong address (called –mail id) then computer instantly gets back to inbox with a “sorry message” like the id entered by you was not found on server. When we send mail from our computer, the first data is sent to web-server proving mailing facility. And then when person logs-on with his id, he can see in inbox all the received mails. We can use software or web-site for this purpose.

             Uses:

1.        Information exchange

2.        Transmitting documents.

3.        Care for customers to stay in touch

4.        Offering discounts for items

5.        Sharing ideas, movies, jokes etc

             Types of –email:

1.                       Web-based:

                                                 Under this, you have to visit web-server (site) in which you want to make id. Click on sign –up button or create new id option. Then provide some details about you with a mailing id with password name. That is all. It’s ready to go. But one thing here, to use this we must visit the web then singing-in or up. Mostly it is provided at free of cost to all users. But if a user wants on pay type then s/he can go for this. We have many such types of web-sites like, by YAHOO, GOOGLE, MICROSOFT ETC.

2.                    Pop/smtp  based:-

                                                                Here, pop means “post office protocol” and smtp means “simple mail transfer protocol. It is a protocol by using which we can receive or send mails/files. We do not need to visit web site but instead we have to use some software like outlook, thunderbird, Eudora etc. there first we have to set the protocol given by ISP under “pop” and “smtp” then we can use this service. To get protocol, we have to pay some charge to ISP. Or some where to use mailing facility, companies (ISP) provide their web-site with a valid username and password. We can also use mailing system through this. Obviously, to get valid username and password, we pay some charge depending on type of service and space.