I.T. for Management

Chapter 5Networking/Internet & Web technologies

Networking• The Computer Network is nothing but a set of

computers connected to each other, mainly for Sharing information, data, programs & resources.

• Networking reduces the cost of doing business since resources are utilized to optimum extent.

• The evolution of newer business models such as the ITES/BPO,the offshore Software etc are an outcome of the Networks be it in Telephony or in terms of computer networks.

Networking• Benefits

• Interaction & communication between various people at locations & perhaps using different types of hardware& software different

• Sharing of Data so that there is consistency of data

• Sharing of expensive devices such as printers• Created newer and previously unthinkable ways

of doing business such as telecom,BPO etc.

Networking

• Broad categories of networking are

LAN, WAN, MANCu Cable, Fiber Cable, WirelessTCP/IP, HTTP ProtocolsStar, Bus, Ring TopologyPacket Switching/Network switchingPeer to Peer Network

Network Topologies

What is a Topology?The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Physical topology should not be confused with logical topology which is the method used to pass information between workstations

Network TopologiesMain Types of Physical Topologies

The following sections discuss the physical topologies used in networks and other related topics.

• Linear Bus• Star• Star-Wired Ring• Tree

Network Topologies

Linear BusA linear bus topology consists of a main run of cable with a terminator at each end (See fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear cable. Ethernet and LocalTalk networks use a linear bus topology.

Network Topologies

dvantages of a Linear Bus Topology Easy to connect a computer or peripheral to a linear bus.

Requires less cable length than a star topology.isadvantages of a Linear Bus Topology

Entire network shuts down if there is a break in the main cable.

Terminators are required at both ends of the backbone cable.

Diffi lt t id tif th bl if th ti

Network Topologies

Star A star topology is designed with each node (file server,

workstations, and peripherals) connected directly to a central network hub or concentrator (See fig. 2).

Data on a star network passes through the hub or concentrator before continuing to its destination.

The hub or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow.

This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable.

Network Topologies

dvantages of a Star Topology

Easy to install and wire.

No disruptions to the network then connecting or removing devices.

Easy to detect faults and to remove parts.

isadvantages of a Star Topology

Requires more cable length than a linear topology.

If the hub or concentrator fails, nodes attached are disabled.

More expensive than linear bus

Network Topologies

TreeA tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable (See fig. 4). Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.

Components of a Network• The Computers are connected to the medium with the

help of network interface cards(NIC)• One of the computers on the network is designed as

controller usually called as Server• Sever usually maintains vital information about network,• Holds shared software& services• Monitors facilities so that problems on network can be

detected& corrected• It act as intelligent device which routes the message to

the appropriate path

Networking Devices

• Common basic network devices:Gateway: device sitting at a network node for interfacing with another network that uses different protocols. Works on OSI layers 4 to 7. Router: a specialized network device that determines the next network point to which to forward a data packet toward its destination. Unlike a gateway, it cannot interface different protocols. Works on OSI layer 3. Bridge: a device that connects multiple network segments along the data link layer. Works on OSI layer 2.

Networking DevicesSwitch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2. Hub: connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time.

Networking DevicesDepending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc). It provides bandwidth which is shared among all the objects, compared to switches, which provide a dedicated connection between individual nodes. Works on OSI layer 1. Repeater: device to amplify or regenerate digital signals received while setting them from one part of a network into another. Works on OSI layer 1.

Network Cabling

What is Network Cabling?Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network

Network Cabling

Unshielded Twisted Pair (UTP) CableTwisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks (See fig. 1).

Network Cabling

Coaxial CableCoaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield (See fig. 3). The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers.

Network Cabling

Fiber Optic CableFiber optic cabling consists of a center glass core surrounded by several layers of protective materials (See fig. 5). It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.

Network Cabling

Specification

10BaseT

10Base2

10Base5

10BaseF

100BaseT

100BaseTX

Cable Type

Unshielded Twisted Pair

Thin Coaxial

Thick Coaxial

Fiber Optic

Unshielded TwistedPair

Unshielded Twisted Pair

Maximum length

100 meters

185 meters

500 meters

2000 meters

100 meters

220 meters

Network Cabling

Wireless LANsNot all networks are connected with cabling; some networks are wireless. Wireless LANs use high frequency radio signals, infrared light beams, or lasers to communicate between the workstations and the file server or hubs. Each workstation and file server on a wireless network has some sort of transceiver/antenna to send and receive the data. Information is relayed between transceivers as if they were physically connected. For longer distance, wireless communications can also take place through cellular telephone technology, microwave transmission, orby satellite.

Network Cabling

Wireless LANs

Wireless networks are great for allowing laptop computers or remote computers to connect to the LAN. Wireless networks are also beneficial in older buildings where it may be difficult or impossible to install cables.

How do Networks Work

Once the physical connection between computers are established ,computers can send messages to each other

A computer wishing to communicate with another needs to do what is known as a “hand Shaking”

All these rules for communication is called protocolsThere are various protocols at various levels of softwareIn practice there are different layers of software each

performing different functionsThere is a well known international model defined by

International Standards Organization

How do Networks WorkOSI Model

Data unit Layer Function

Hostlayers

Data

Application Network process to application

Presentation Data representation and encryption

Session Inter host communication

Segments Transport End-to-end connections and reliability (TCP)

Medialayers

Packets Network Path determination and logical addressing (IP)

Frames Data link Physical addressing (MAC & LLC)

Bits Physical Media, signal and binary transmission

How do Networks Work

Packet switching, in computer networking and telecommunications, is the communications paradigm in which packets (units of information carriage) are routedbetween nodes over data links shared with other traffic. This contrasts with the other principal paradigm, circuit

switching, which sets up a dedicated connection between the two nodes for their exclusive use for the duration of the

communication. Packet switching is used to optimize the use of the bandwidth available in a network, to minimize the transmission latency (i.e. the time it takes for data to pass

across the network), and to increase robustness of communication.

How do Networks Work

Packet routingPackets are routed to their destination as determined by a routing algorithm. The routing algorithm can create paths based on various metrics and desirable qualities of the routing path. For example, low latency may be of paramount concern and everything else is secondary, or a minimum hop count.It's also entirely possible to have to weigh the various metrics against each other. For example, reducing the hop count could increase the latency to an unacceptable limit and some kind of balance would need to be found. For multi-parameter optimization, some form of optimizationmay be needed.

How do Networks Work

A peer-to-peer system is a distributed system whose component nodes participate in similar roles, and are therefore peers to each other. Peer-to-peer can be viewed as decentralized network architecture. In contrast, a client-server architecture implies a sharp distinction between the clients which request and consume services, and servers which provide services.Even though the nodes have similar roles, there may still be some structure to the peer-to-peer system, and it usually possesses some degree of self-organizationwhere each node finds its peers and helps maintain the system structure. ……. Cont

How do Networks Work

This makes a peer-to-peer network node more complex than a client in client-server system. The main benefits of peer-to-peer system are scalability, fault-tolerance, and the lack of resource bottlenecks in servers.

The peer-to-peer concept is related to Distributed computing and Swarm intelligence, but differs from them in that peer-to-peer nodes usually serve their own needs acting as Intelligent agents, instead of performing a collective function as a group.

Recently, the concept has achieved recognition in the general public in the context of peer-to-peer file sharing which is one application of peer-to-peer networks.

Wi-Fi in campus

For computers to use the wireless facility requires 2 things

Each computer must be fitted with wireless card.most Laptops tend to have this facility

The server would send information thru a LAN.A wireless access point which is a special deviceisalso connected to the LAN

This device converts the signals received from the LAN & broadcasts them into signal suitable for LAN

Wi-Fi in campus

Any products tested and approved as "Wi-Fi Certified" (a registered trademark) by the Wi-Fi Alliance are certified as interoperable with each other, even if they are from different manufacturers. A user with a "Wi-Fi Certified" product can use any brand of access point with any other brand of client hardware that also is certified. Typically, however, any Wi-Fi product using the same radio frequency (for example, 2.4GHz for 802.11b or 11g, 5GHz for 802.11a) will work with any other, even if not "Wi-Fi Certified." .

Wi-Fi in campus

The Advantages of Wi-Fi in a campus It can be installed very easily& quickly no civil

work no cable laying, antenna can be deployed in a single day

User using laptops PDA can move devices to any locations without getting disconnected

Thus it provides access anywhere,anytime within the campus

This can increase productivity of the work force

Plain Old Telephone systems

Short for plain old telephone service, which refers to the standard telephone service that most homes use. In contrast, telephone services based on high-speed, digitalcommunications lines, such as ISDN and FDDI, are not POTS.The main distinctions between POTS and non-POTS services are speed and bandwidth. POTS is generally restricted to about 52 Kbps (52,000 bits per second). The POTS network is also called the public switched telephone network (PSTN).

Plain Old Telephone systems

Plain old telephone service, or POTS, is a term which describes the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network nearly everywhere in the world. The name is a reflection of the telephone service still available after the advent of more advanced forms of telephony such as ISDN, mobile phones and VoIP. It has been available almost since the introduction of the public telephone system in the late 19th century, in a form mostly unchanged to the normal user despite the introduction of Touch-Tone dialing, electronic telephone exchanges and fiber-optic communication into the public switched

telephone network (PSTN).

VSAT based network

A 2.5m parabolic dish antenna for bidirectional Satellite Internet Access.A Very Small Aperture Terminal (VSAT), is a 2-way satellite ground station with a dish antenna that is smaller than 3 meters. VSATs are most commonly used to transmit credit card or RFIDdata for point of sale transactions, and for the provision of Satellite Internet access to remote locations.

VSAT Advantages

The advances of computer technology have changed the satellite business situation of FSS (Fixed satellite services). This FSS satellite system has a huge capacity with relatively low price system including prices for providing VSATs terminal. This tendency causes the FSS system become a very interesting business. Nowadays, the regulation of satellite services goes to the subscribers using VSAT terminal. These FSS satellite systems provide various applications for subscribers. These applications are not only limited in phone conversation, faximile, TV broadcast or high speed communication services, but also for new services such as direct to home (DTH), internet access, video conferencing, Satellite News Gathering (SNG), frame relay, Digital Audio Broadcasting (DAB) and others.Basically, these systems are applicable for providing various excellent quality services, because they create efficient communication system, both for home dwellers and business people.

ISDN

Integrated Services Digital Network (ISDN) is a circuit-switched telephone network system, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds than that available with the PSTN system. More broadly, ISDN is a set of protocols for establishing and breaking circuit switched connections, and for advanced call features for the user.In a videoconference, ISDN provides simultaneous voice, video, and text transmission between individual desktop videoconferencing systems and group (room) videoconferencing systems.

Advantages of ISDN

The purpose of the ISDN is to provide fully integrated digital services to the users.These services fall under three categories: bearer

services, supplementary services and teleservices.Being digital they carry signals without much distortionIt can carry all types of signals voice data & multimediaISDN is typically used for vedio conferance

Internet

The Internet is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various informationand services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.

Internet Protocols•IP (Internet Protocol), which defines the datagrams or packets that carry blocks of data from one node to another. The vast majority of today's Internet uses version four of the IP protocol (i.e. IPv4), and although IPv6 is standardized, it exists only as "islands" of connectivity, and there are many ISPs without any IPv6 connectivity. [1]•Next come TCP (Transmission Control Protocol), UDP (User Datagram Protocol), and ICMP (Internet Control Message Protocol) -the protocols by which data is transmitted. TCP makes a virtual 'connection', which gives some level of guarantee of reliability. UDP is a best-effort, connectionless transport, in which data packets that arelost in transit will not be re-sent. ICMP is connectionless, it is used for control and signaling purposes. •On top comes the application protocol. This defines the specific messages and data formats sent and understood by the applications running at each end of the communication.

How does a dial up user get connected to internet

The dial up users computer is not a host on the internet.He has to connect to the internet service provider such as VSNL

After authenticating the user,VSNL server would assign a temporary IP number from a shared pool of IP numbers

Once your machine gets a temporary IP address and is connected to internet via VSNL servers your machine becomes a host on the internet

…..Cont

How does a dial up user get connected to internet

Hence someone wishes to chat with you can type your temporary IP number & access your machine

Once you log out of internet the IP number is de allocated & is available in the share pool with the service provider

The Worldwide web is the most popular application on the internet

Hypertext Mark up language (HTML) provides a standard tag which identifies each block within

document

Web Server

The term Web server can mean one of two things:1.A computer that is responsible for accepting HTTP requests from clients, which are known as Web browsers, and serving them HTTPresponses along with optional data contents, which usually are Web pages such as HTMLdocuments and linked objects (images, etc.). 2.A computer program that provides the functionality described in the first sense of the term. …… Cont

Web ServerAlthough Web server programs differ in detail, they all share some basic common features.

1.HTTP: every Web server program operates by accepting HTTP requests from the network, and providing an HTTP response to the requester. The HTTP response typically consists of an HTML document, but can also be a raw text file, an image, or some other type of document; if something bad is found in client request or while trying to serve the request, a Web server has to send an error response which may include some custom HTML or text messages to better explain the problem to end users.

Logging: usually Web servers have also the capability of logging some detailed information, about client requests and server responses, to log files; this allows the Webmaster to collect statistics by running log analyzers on log files.

Web Server

The inside/rear of a Dell PowerEdge web server, which is using the Apache web server software

Web Server

The web server & documents are located by a user with the help of uniform resource locator(URL) which is like web address

The user types the URL on the search barURL is converted into IP address of the web

server and the browser request is sent to the web server

The web server locates the document based on the registration which information which it has about the document It sends document across

internet to the IP address

Domain Names• The term domain name has multiple related

meanings:A name that identifies a computer or computers on the internet. These names appear as a component of a Web site's URL, e.g. www.wikipedia.org. This type of domain name is also called a hostname. The product that Domain name registrarsprovide to their customers. These names are often called registered domain names.

Domain Names

They are sometimes colloquially (and incorrectly) referred to by marketers as "web addresses".

Names used for other purposes in the Domain Name System (DNS), for example the special name which follows the @ sign in an emailaddress, or the Top-level domains like .com, or the names used by the Session Initiation Protocol (VoIP), or DomainKeys.

Domain Names

• The following example illustrates the difference between a URL (Uniform Resource Locator) and a domain name:

• URL: http://www.example.net/index.html • Domain name: www.example.net • Registered domain name: example.net

……cont

Domain NamesAs a general rule, the IP address and the server name are interchangeable. For most Internet services, the server will not have any way to know which was used. However, the explosion of interest in the Web means that there are far more Web sites than servers. To accommodate this, the hypertext transfer protocol (HTTP) specifies that the client tells the server which name is being used. This way, one server with one IP address can provide different sites for different domain names.

HTTP

Short for Hyper Text Transfer Protocol, the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.

HTTP

The other main standard that controls how the World Wide Web works is HTML, which covers how Web pages are formatted and displayed. HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it. This is the main reason that it is difficult to implement Web sites that react intelligently to user input. This shortcoming of HTTP is being addressed in a number of new technologies, including ActiveX, Java, JavaScript and cookies.

Cookies

The main purpose of cookies is to identify users and possibly prepare customized Web pages for them.When you enter a Web site using cookies, you may be asked to fill out a form providing such information as your name and interests. This information is packaged into a cookie and sent to your Web browser which stores it for later use. The next time you go to the same Web site, your browser will send the cookie to the Web server.

Cookies

The server can use this information to present you with custom Web pages. So, for example, instead of seeing just a generic welcome page you might see a welcome page with your name on it. The name cookie derives from UNIX objects called magic cookies.These are tokens that are attached to a user or program and

change depending on the areas entered by the user or program

Websites

A website (or Web site) is a collection of web pages, images, videos and other digital assets and hosted on a particular domain or subdomain on the World Wide Web.A web page is a document, typically written in HTML, that is almost always accessible via HTTP, a protocol that transfers information from the website's server to display in the user's web browser.

Websites

All publicly accessible websites are seen collectively as constituting the "World Wide Web".The pages of websites can usually be accessed from a common root URL called the homepage, and usually reside on the same physical server. The URLs of the pages organize them into a hierarchy, although the hyperlinks between them control how the reader perceives the overall structure and how the traffic flows between the different parts of the sites.

Websites

Some websites require a subscription to access some or all of their content. Examples of subscription sites include many business sites, parts of many news sites, gaming sites, message boards, Web-based e-mail services, and sites providing real-time stock market data.As of March 2007 there are over 110 million websites in total on the world wide web.

Websites

The first on-line website appeared in 1991. On 30 April1993, CERN announced that the World Wide Web would be free to anyone..

OverviewOrganized by function a websitemay be

•a personal website •a business website •a government website or •a non-profit organization website.

History

Websites

Websites are written in, or dynamically converted to, HTML (Hyper Text Markup Language) and are accessed using a software program called a Web browser, also known as an HTTP client. Web pages can be viewed or otherwise accessed from a range of computer based and Internet enabled devices of various sizes, including desktop computers, laptop computers, PDAs and cell phones.

Websites

A website is hosted on a computer system known as a web server, also called an HTTP server, and these terms can also refer to the software that runs on these system and that retrieves and delivers the Web pages in response to requests from the website users. Apache is the most commonly used Web server software

WebsitesA static website, is one that has web pages stored on the server in the same form as the user will view them. They are edited using three broad categories of software:

•Text editors. such as Notepad or TextEdit, where the HTML is manipulated directly within the editor program •WYSIWYG editors. such as Microsoft FrontPage and Macromedia Dreamweaver, where the site is edited using a GUI interface and the underlying HTML is generated automatically by the editor software

WebsitesTemplate-based editors, such as Rapidweaver and iWeb, which allow users to quickly create and upload websites to a web server without having to know anything about HTML, as they just pick a suitable template from a palette and add pictures and text to it in a DTP-like fashion without ever having to see any HTML code. A dynamic website is one that has frequently changing information or collates information on the hop each time a page is requested. For example, it would call various bits of information from a database and put them together in a pre-defined format to present the reader with a coherent page.

Websites

It interacts with users in a variety of ways including by reading cookies recognizing users' previous history, session variables, server side variables etc., or by using direct interaction (form elements, mouseovers, etc.). A A site can display the current state of a dialogue between users, monitor a changing situation, or provide information in some way personalized to the requirements of the individual user.

Websites

Suppliers can now viewThe requirement of the customerBid for the requirementReceived a confirmed order from the customer

via the WebsiteUpdates the information on deliveries sent to the

customerGet acknowledgement & receive payment for

deliveries

Types of websites

There are many varieties of Web sites, each specialising in a particular type of content or use, and they may be arbitrarily classified in any number of ways. A few such classifications might include:[original research?]

Affiliate: enabled portal that renders not only its custom CMSbut also syndicated content from other content providers for an agreed fee. There are usually three relationship tiers. Affiliate Agencies (e.g., Commission Junction), Advertisers (e.g., Ebay) and consumer (e.g., Yahoo). Archive site: used to preserve valuable electronic content threatened with extinction. Two examples are: Internet Archive, which since 1996 has preserved billions of old (and new) Web pages; and Google Groups, which in early 2005 was archiving over 845,000,000 messages posted to Usenet news/discussion groups.

Types of websites

Blog (or web log) site: sites generally used to post online diaries which may include discussion forums (e.g., blogger, Xanga). Corporate website: used to provide background information about a business, organization, or service. Commerce site or eCommerce site: for purchasing goods, such as Amazon.com. Community site: a site where persons with similar interests communicate with each other, usually by chat or message boards, such as MySpace. Database site: a site whose main use is the search and display of a specific database's content such as the Internet Movie Database or the Political Graveyard. Development site: a site whose purpose is to provide information and resources related to software development, Web design and the like.

Types of websites

Types of websitesDownload site: strictly used for downloading electronic content, such as software, game demos or computer wallpaper. Employment site: allows employers to post job requirements for a position or positions and prospective employees to fill an application. Game site: a site that is itself a game or "playground" where many people come to play, such as MSN Games and Pogo.com. Geodomain refers to domain names that are the same as those of geographic entities, such as cities and countries. For example, Richmond.com is the geodomain for Richmond, Virginia. Gripe site: a site devoted to the critique of a person, place, corporation, government, or institution. Humor site: satirizes, parodies or otherwise exists solely to amuse

Types of WebsiteInformation site: contains content that is intended to inform visitors, but not necessarily for commercial purposes, such as: RateMyProfessors.com, Free Internet Lexicon and Encyclopedia. Most government, educational and non-profit institutions have an informational site. Java applet site: contains software to run over the Web as a Web application. Mirror (computing) site: A complete reproduction of a website. News site: similar to an information site, but dedicated to dispensing news and commentary. Personal homepage: run by an individual or a small group (such as a family) that contains information or any content that the individual wishes to include.

Types of websitePhish site: a website created to fraudulently acquire sensitive information, such as passwords and credit card details, by masquerading as a trustworthy person or business (such as Social Security Administration, PayPal) in an electronic communication. (see Phishing). Political site: A site on which people may voice political views. Pornography (porn) site: a site that shows pornographic images and videos. Rating site: A site on which people can praise or disparage what is featured (e.g. ratemycar.com). Review site: A site on which people can post reviews for products or services. Search engine site: a site that provides general information and is intended as a gateway or lookup for other sites. A pure example is Google, and the most widely known extended type is Yahoo!.

Email

An E-mail MessageAccording to Darwin Magazine: Prime Movers, the first e-mail message was sent in 1971 by an engineer named Ray Tomlinson. Prior to this, you could only send messages to users on a single machine. Tomlinson's breakthrough was the ability to send messages to other machines on the Internet, using the @ sign to designate the receiving machine.

EmailAn e-mail message has always been nothing more

than a simple text message -- a piece of text sent to a recipient. In the beginning and even today, e-mail messages tend to be short pieces of text, although the ability to add attachments now makes many e-mail messages quite long. Even with attachments, however, e-mail messages continue to be text messages -- we'll see why when we get to the section on attachments.

Email

The Real E-mail SystemFor the vast majority of people right now, the real e-mail system consists of two different servers running on a server machine. One is called the SMTP server, where SMTP stands for Simple Mail Transfer Protocol. The SMTP server handles outgoing mail. The other is either a POP3 server or an IMAP server, both of which handle incoming mail. POP stands for Post Office Protocol, and IMAP stands for Internet Mail Access Protocol.

Email

A typical e-mail server looks like this:

The SMTP server listens on well-known port number 25, POP3 listens on port 110 and IMAP uses port 143 (see How Web Servers Work for details on ports).

Email

The SMTP ServerWhenever you send a piece of e-mail, your e-mail client interacts with the SMTP server to handle the sending. The SMTP server on your host may have conversations with other SMTP servers to actually deliver the e-mail.

Email

Email is very effective means of communicationIt is fast & asynchronousEmail is quite often a source of spreading a

virusesEmail created new opportunities for marketingCost remains same even if number of recipients

increase

SPAM

The term "spam" is Internet slang that refers to unsolicited commercial email (UCE) or unsolicited bulk email (UBE). Some people refer to this kind of communication as junk email to equate it with the paper junk mail that comes through the US Mail. Unsolicited email is email that you did not request; it most often contains advertisements for services or products. There are very few reputable marketers using UCE to advertise goods and services.

SPAM

The most commonly seen spam includes the following: · Phishing scams, a very popular and dangerous form of email fraud· Foreign bank scams or advance fee fraud schemes· Pyramid schemes, including multilevel marketing (MLM)· Other "Get Rich Quick" or "Make Money Fast" (MMF) schemes· Quack health products and remedies

….Cont

SPAM

· Ads for pornographic web sites · Offers of software for collecting email addresses and sending UCE · Offers of bulk emailing services for sending UCE · Chain letters (for more information, see the Knowledge Base document What is electronic chain mail?) · Illegally pirated software ("Warez")

Searching on the Net

Browsing on net is most popular application Search engines such as msn, Google ,Yahoo are

frequently usedMany search engines used provide advance

features & use special syntax for helping the userNot surprising that advertising companies in the

business of website development always prefer to ensure there site appears in top 10 websites

I.T. for Management

End of Chapter 5