what is intranet

8/14/2019 What is Intranet

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INTRANETINTRANETUNIT - IIUNIT - II


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What is IntranetWhat is IntranetAn intranet is a private network that isAn intranet is a private network that is

contained within an enterprise.contained within an enterprise.

It may consist of many interlinked local areaIt may consist of many interlinked local area

networks and also use leased lines in thenetworks and also use leased lines in the

wide area network.wide area network.The main purpose of an intranet is to shareThe main purpose of an intranet is to share

company information and computingcompany information and computing

resources among employees.resources among employees.

An intranet can also be used to facilitateAn intranet can also be used to facilitate

working in groups and for teleconferences.working in groups and for teleconferences.


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An intranet uses TCP/IP, HTTP, and otherAn intranet uses TCP/IP, HTTP, and otherInternet protocols and in general looksInternet protocols and in general lookslike a private version of the Internet.like a private version of the Internet.

Typically, larger enterprises allow usersTypically, larger enterprises allow userswithin their intranet to access the publicwithin their intranet to access the publicInternet through firewall servers thatInternet through firewall servers that

have the ability to screen messages inhave the ability to screen messages inboth directions so that company securityboth directions so that company securityis maintained.is maintained.

When part of an intranet is madeWhen part of an intranet is made

accessible to customers, partners,accessible to customers, partners,suppliers, or others outside the company,suppliers, or others outside the company,that part becomes part of anthat part becomes part of an extranetextranet..


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Planning an IntranetPlanning an IntranetThe purpose and goals of the intranetThe purpose and goals of the intranet Persons or departments responsible forPersons or departments responsible for

implementation and managementimplementation and management Functional plans, information architecture, pageFunctional plans, information architecture, page

layouts, design.layouts, design.

Implementation schedules and phase-out of existingImplementation schedules and phase-out of existingsystemssystems Defining and implementing security of the intranetDefining and implementing security of the intranet How to ensure it is within legal boundaries and otherHow to ensure it is within legal boundaries and other

constraintsconstraints

Level of interactivity (eg wikis, on-line forms)Level of interactivity (eg wikis, on-line forms)desired.desired. Is the input of new data and updating of existingIs the input of new data and updating of existing

data to be centrally controlled or devolveddata to be centrally controlled or devolved


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c uac uaImplementationImplementation

The actual implementation of intranet includesThe actual implementation of intranet includes

following steps:following steps:

Securing senior management support and funding.Securing senior management support and funding.

Business requirements analysis.Business requirements analysis.

Setting up web server access using a TCP/IP network.Setting up web server access using a TCP/IP network.

Installing required user applications on computers.Installing required user applications on computers.

Creation of document framework for the content to beCreation of document framework for the content to be

hosted.hosted.

User involvement in testing and promoting use of intranet.User involvement in testing and promoting use of intranet.

Ongoing measurement and evaluation, including throughOngoing measurement and evaluation, including throughbenchmarking against other intranets.benchmarking against other intranets.


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Requirements &Requirements &

RecommendationsRecommendations Network ServiceNetwork Service

Directory ServiceDirectory Service

Security ServiceSecurity Service

Messaging ServiceMessaging Service

Application ServiceApplication Service

File ServiceFile Service

Database ServiceDatabase Service

Cal Poly Pomona WebCal Poly Pomona Web


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Types of IntranetTypes of Intranet

CollaborationPlatform

InternalWebsite

DistributedIntranet


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The CollaborationThe Collaboration

PlatformPlatform This type is very big on two-wayThis type is very big on two-way

publishing.publishing.

Users publish just as much as theyUsers publish just as much as they

consume.consume. This type of intranet is big onThis type of intranet is big on

discussion forums and other ways todiscussion forums and other ways to

people to connect with each other.people to connect with each other. Information tends to be less formal,Information tends to be less formal,

more conversational.more conversational.


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The Internal WebsiteThe Internal WebsiteThis type is based on one-way publishing.This type is based on one-way publishing.People who interact with it are divided intoPeople who interact with it are divided intotwo groups: consumers and publishers.two groups: consumers and publishers.

There is a defined admin side to it whichThere is a defined admin side to it which

comparatively few people have access.comparatively few people have access. Information is reviewed before itsInformation is reviewed before its

published, and its often subject to workflowpublished, and its often subject to workflowand approvals.and approvals.

The intranet is structured just like a publicThe intranet is structured just like a publicWeb site, it just happens to be behind theWeb site, it just happens to be behind thefirewall.firewall.


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The Distributed IntranetThe Distributed Intranet In larger organizations, intranet very quicklyIn larger organizations, intranet very quickly

becomes decentralized.becomes decentralized. It does not end up with a single, definableIt does not end up with a single, definable

intranet, but with dozens or even hundredsintranet, but with dozens or even hundreds

of small applications (e.g. - a phone directory,of small applications (e.g. - a phone directory,

an announcements system, a documentan announcements system, a document

library) that are grouped around commonlibrary) that are grouped around common

infrastructure, like a centralized userinfrastructure, like a centralized user

database and a centralized store of designdatabase and a centralized store of design

elements so all the mini-applications can lookelements so all the mini-applications can look

the same.the same.


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Web publishingWeb publishing It allows 'It allows 'cumbersome'cumbersome' corporate knowledge tocorporate knowledge to

be maintained and easily accessed throughout thebe maintained and easily accessed throughout the

company using hypermedia and Webcompany using hypermedia and Webtechnologies.technologies.

Business operations and managementBusiness operations and management Intranets are also being used as a platform forIntranets are also being used as a platform for

developing and deploying applications to supportdeveloping and deploying applications to support

business operations and decisions across thebusiness operations and decisions across theinternetworked enterprise.internetworked enterprise.

Cost-effectiveCost-effective Users can view information and data via web-Users can view information and data via web-

browser rather than maintaining physicalbrowser rather than maintaining physicaldocuments such as procedure manuals, internaldocuments such as procedure manuals, internalphone list and requisition forms.phone list and requisition forms.


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Cross-platform CapabilityCross-platform Capability Standards-compliant web browsers areStandards-compliant web browsers are

available for Windows, Mac, and UNIX.available for Windows, Mac, and UNIX.

Immediate UpdatesImmediate Updates

When dealing with the public in any capacity,When dealing with the public in any capacity,

laws/specifications/parameters can change.laws/specifications/parameters can change.

Promote common corporate culturePromote common corporate culture Every user is viewing the same informationEvery user is viewing the same information

within the Intranet.within the Intranet.

Enhance CollaborationEnhance Collaboration

With information easily accessible by allWith information easily accessible by all

authorised users, teamwork is enabled.authorised users, teamwork is enabled.


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IntranetIntranet

DisadvantagesDisadvantagesManagement concerns Management fears loss of control

Hidden or unknown complexity and costsPotential for chaos

Security concerns

Unauthorized accessAbuse of accessDenial of servicePacket sniffing

Productivity concernsOverabundance of informationInformation overload lowers productivityUsers set up own web pages


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Intranet ArchitectureIntranet Architecture Before discussing the Intranet Architecture aBefore discussing the Intranet Architecture a

few background concepts need to befew background concepts need to beintroduced.introduced.

Sources of InformationSources of Information Formal informationFormal information

This is the information with which the formal managementThis is the information with which the formal managementinfrastructure is most concerned.infrastructure is most concerned.

Project/group informationProject/group information It is used to communicate and share ideas, coordinate activities orIt is used to communicate and share ideas, coordinate activities or

manage the development and approval of content that eventuallymanage the development and approval of content that eventuallywill become formalwill become formal

Informal informationInformal information In the informal information the URL can be given to the interestedIn the informal information the URL can be given to the interested

parties, and the latest version can be read and tracked as itparties, and the latest version can be read and tracked as itchanges.changes.


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Types of PagesTypes of Pages

Content pagesContent pagesContent pages can take many forms.Content pages can take many forms.

They may be static pages, like the ones youThey may be static pages, like the ones you

are reading here, or they may be active pagesare reading here, or they may be active pages

where the page content is generated.where the page content is generated.

Broker pagesBroker pagesBroker pages serve an explicitly definedBroker pages serve an explicitly defined

audience or function.audience or function.

A hyperlink broker page contains links to otherA hyperlink broker page contains links to otherpages, in context.pages, in context.

Many of the pages with which we already areMany of the pages with which we already are

familiar are broker pagesfamiliar are broker pages

Th I t tT I t t


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The IntranetT e IntranetInfrastructureInfrastructure

The Enterprise MapThe Enterprise Map

Shadow MapsShadow Maps

General BrokeringGeneral Brokering

Workflow ManagementWorkflow ManagementAccess to Database InformationAccess to Database Information


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Enterprise MapEnterprise Map A structured set of broker pages can be very usefulA structured set of broker pages can be very useful

for managing the life cycle of published content. Wefor managing the life cycle of published content. Wecall this the Enterprise Mapcall this the Enterprise Map

The Enterprise Map also does not have to be basedThe Enterprise Map also does not have to be basedon organization. It could be a logical map where theon organization. It could be a logical map where thetop level is the mission, the next level the majortop level is the mission, the next level the major

focuses required to accomplish the mission, and sofocuses required to accomplish the mission, and soon, down to the content level.on, down to the content level.

the Enterprise Map begins with a top page, ownedthe Enterprise Map begins with a top page, ownedby the CIO and /or CEO (with responsibility usuallyby the CIO and /or CEO (with responsibility usuallydelegated to the Web Administrator).delegated to the Web Administrator).

The Map provides a commitment (or accountability)The Map provides a commitment (or accountability)view of all the formal content in the enterprise.view of all the formal content in the enterprise.


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Shadow MapShadow MapThe Shadow Map works the same way asThe Shadow Map works the same way as

the Enterprise Map, but it is not generallythe Enterprise Map, but it is not generallyadvertised and can be protected byadvertised and can be protected by

passwords or other access controls.passwords or other access controls.

A Shadow Map continues down to theA Shadow Map continues down to theauthor level.author level.

The author maintains an Index Page thatThe author maintains an Index Page that

is divided into two sections, workis divided into two sections, work

commitments and work completed.commitments and work completed.

Finally work completed must meet theFinally work completed must meet the

work commitments.work commitments.


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Shadow Page DiagramShadow Page Diagram


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General BrokingGeneral BrokingA broker may provide information to users inA broker may provide information to users in

the context of specific processes, providingthe context of specific processes, providingstructure for efficiency and consistency.structure for efficiency and consistency.

Most knowledge worker jobs today involveMost knowledge worker jobs today involvesome form of information brokering.some form of information brokering.

An individual may start the page for himself,An individual may start the page for himself,these pages can be a valuable way to identifythese pages can be a valuable way to identifyand quickly meet new requirements.and quickly meet new requirements.

However there is no guarantee that theHowever there is no guarantee that the

content in these pages are verified or that thecontent in these pages are verified or that theauthor will keep the content current.author will keep the content current.


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DiagramDiagram


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Workflow ManagementWorkflow Management

Workflow management is a relatively newWorkflow management is a relatively newfocus for the Intranet.focus for the Intranet.

Email, threaded-mail discussion groups andEmail, threaded-mail discussion groups and

news groups provide forums for discussionnews groups provide forums for discussion

and resolution of issues.and resolution of issues.The HTML "mailto:" function has been usedThe HTML "mailto:" function has been used

to provide reviewers with easy connectionsto provide reviewers with easy connections

through their browser to these forums.through their browser to these forums.


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Access to DatabaseAccess to Database

InformationInformationThree models of access can beThree models of access can be

identified:identified:

Automatic tailoring of page contentAutomatic tailoring of page content

User specified database requestsUser specified database requests

User initiated database updatesUser initiated database updates

Designing an IntranetDesigning an Intranet


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Designing an IntranetDesigning an Intranet(Building Corporate Wide(Building Corporate Wide

WebWeb ))Points to keep in mind whilePoints to keep in mind whiledesigning the Intranetdesigning the Intranet Integrating Information DesignIntegrating Information Design

Dont Overlook DesignDont Overlook Design

Implementation of Tasks rather thanImplementation of Tasks rather than

DocumentsDocuments

Organize tasks into larger processesOrganize tasks into larger processes Virtual WorkgroupsVirtual Workgroups

Reflection of IntranetReflection of Intranet


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Integrating InformationIntegrating Information

DesignDesign It is must to integrate all information collectedIt is must to integrate all information collected

in the organization to develop the intranet.in the organization to develop the intranet.

All the information must be according to theAll the information must be according to the

business needs and business planning.business needs and business planning.

Focusing on processes rather than departmentsFocusing on processes rather than departmentsis a widely-hailed business trend.is a widely-hailed business trend.

Intranet should help employees in collaboratingIntranet should help employees in collaborating

on business process such as producton business process such as product

development or any order fulfillment.development or any order fulfillment.


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Dont Overlook DesignDont Overlook Design

An intranet needs to be carefullyAn intranet needs to be carefullydesigned to help employees accessdesigned to help employees accessinformation and collaborate effectively.information and collaborate effectively.

None of the design should present anyNone of the design should present anyirrelevant information of the company.irrelevant information of the company.

There must be an organization chart ofThere must be an organization chart ofthe company to represent the companythe company to represent the companyflow chart to outsiders and as well to itsflow chart to outsiders and as well to itsemployees.employees.


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Implementation of TasksImplementation of Tasks

rather than Documentsrather than Documents

Intranet is not just a collection of documents ratherIntranet is not just a collection of documents rather

it is the collection of information.it is the collection of information.

Intranet users actually use documents to completeIntranet users actually use documents to complete

the tasks.the tasks.

These task can be organized in a way that allThese task can be organized in a way that all

process should be done accurately.process should be done accurately.

Finally on the basis of these tasks employees doesFinally on the basis of these tasks employees does

different functions, as requireddifferent functions, as required


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Organize tasks into largerOrganize tasks into larger

processesprocesses

It is required that all isolated tasks areIt is required that all isolated tasks arecollected together and make a largercollected together and make a largerprocess.process.

The most important processes in aThe most important processes in acompany are those that create value forcompany are those that create value fora customer.a customer.

Processes can be relatively distinct, suchProcesses can be relatively distinct, such

as developing or selling products.as developing or selling products.So all the processes must be handled in aSo all the processes must be handled in a

way that for intranet users it should beway that for intranet users it should be

an easy task to perform.an easy task to perform.


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Virtual WorkgroupsVirtual Workgroups

For intranet users there must be virtualFor intranet users there must be virtualworkgroup to work together.workgroup to work together. Intranet can also bring togetherIntranet can also bring together

employees and partners who areemployees and partners who are

geographically isolated to work ongeographically isolated to work oncommon problems.common problems.

By putting all people together they canBy putting all people together they can

work on single task with their best.work on single task with their best.The central to the value of an intranetThe central to the value of an intranet

is the design of virtual spaces, whichis the design of virtual spaces, whichpromotes new forms of collaboration,promotes new forms of collaboration,

but in being paid less attention.but in being paid less attention.


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Reflection of IntranetReflection of Intranet

An intranet is actually the reflection ofAn intranet is actually the reflection ofthe company.the company.

By seeing the intranet of any companyBy seeing the intranet of any company

people can make decision how thepeople can make decision how thecompany can be.company can be.

An intranet that reflects the culture of itsAn intranet that reflects the culture of itscompany will make employees feel morecompany will make employees feel moreat home.at home.

For the intranet to be successful, it mustFor the intranet to be successful, it mustprovide ways of empowering allprovide ways of empowering all

employees.employees.


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HTTP ProtocolsHTTP Protocols

HTTP stands forHTTP stands for Hypertext TransferHypertext Transfer

Protocol.Protocol.

It is an TCP/IP based communicationIt is an TCP/IP based communication

protocol which is used to deliverprotocol which is used to deliver

virtually all files and other data,virtually all files and other data,collectively called resources, on thecollectively called resources, on the

World Wide Web.World Wide Web.

These resources could be HTMLThese resources could be HTMLfiles, image files, query results, orfiles, image files, query results, or

anything else.anything else.


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Important things aboutImportant things about

HTTPHTTP HTTP is connectionless:HTTP is connectionless:

After a request is made, the client disconnects fromAfter a request is made, the client disconnects fromthe server and waits for a response. The serverthe server and waits for a response. The servermust re-establish the connection after it process themust re-establish the connection after it process therequest.request.

HTTP is media independent:HTTP is media independent: Any type of data can be sent by HTTP as long asAny type of data can be sent by HTTP as long as

both the client and server know how to handle theboth the client and server know how to handle thedata content. How content is handled is determineddata content. How content is handled is determinedby the MIME specification.by the MIME specification.

HTTP is stateless:HTTP is stateless:

This is a direct result of HTTP's beingThis is a direct result of HTTP's beingconnectionless. The server and client are aware ofconnectionless. The server and client are aware ofeach other only during a request. Afterwards, eacheach other only during a request. Afterwards, eachforgets the other. For this reason neither the clientforgets the other. For this reason neither the clientnor the browser can retain information betweennor the browser can retain information betweendifferent request across the web pages.different request across the web pages.


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HTTP Protocol DiagramHTTP Protocol Diagram


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Request MessageRequest Message

The Request Message of HTTP consistsThe Request Message of HTTP consists

of the following:of the following: An initial line An initial line

Zero or more header lines Zero or more header lines

A blank line ie. a A blank line ie. a

An optional message body like file, queryAn optional message body like file, query

data or query output.data or query output.


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REQUEST METHODS

SAFE METHODS UNSAFEMETHODS

Methods are used onlyfor information retrievaland should not change

the state of the server.

Ex: HEAD, GET,OPTIONS, TRCE

Methods are usedfor making changesin information in

the server.

Ex: POST, PUT,DELETE


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Request MethodsRequest Methods HEADHEAD

This method is often used for testingThis method is often used for testinghypertext links for validity, accessibility, andhypertext links for validity, accessibility, andrecent modification.recent modification.

GETGET

The GET method is used to retrieve whateverThe GET method is used to retrieve whateverinformation (in the form of an entity) isinformation (in the form of an entity) isidentified by the Request-URI.identified by the Request-URI.

POSTPOST

The POST method is used to request that theThe POST method is used to request that theorigin server accept the entity enclosed inorigin server accept the entity enclosed inthe request as a new subordinate of thethe request as a new subordinate of theresource identified by the Request-URI in theresource identified by the Request-URI in theRequest-Line.Request-Line.


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Request MethodsRequest Methods

PUTPUT Put method is used to upload aPut method is used to upload a

representation of the specified resources.representation of the specified resources.

DELETEDELETEThe DELETE method requests that theThe DELETE method requests that the

origin server delete the resourceorigin server delete the resource

identified by the Request-URI.identified by the Request-URI.

TRACETRACEThe TRACE method is used to invoke aThe TRACE method is used to invoke a

remote, application-layer loop- back of theremote, application-layer loop- back of the

request message.request message.


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Request MethodsRequest Methods

OPTIONSOPTIONSThe OPTIONS method represents aThe OPTIONS method represents a

request for information about therequest for information about the

communication options available on thecommunication options available on the

request/response chain identified by therequest/response chain identified by theRequest-URI.Request-URI.

CONNECTCONNECT

This method is used to convert theThis method is used to convert therequest connection to a transparentrequest connection to a transparent

TCP/IP tunnel.TCP/IP tunnel.


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HTTP VersionsHTTP VersionsHTTP 1.0HTTP 1.0

This is the first protocol version inThis is the first protocol version incommunications and mainly used by proxycommunications and mainly used by proxyservers.servers.

HTTP 1.1HTTP 1.1 It is the current version. It allows requestIt is the current version. It allows request

pipelining, multiple user request to be sent atpipelining, multiple user request to be sent atthe same time.the same time.

HTTP 1.2HTTP 1.2This is the working draft of Protocol ExtensionThis is the working draft of Protocol Extension

Protocol. It was published in Feb2000. This isProtocol. It was published in Feb2000. This isthe future protocol version.the future protocol version.

S S CO SSTATUS CODES


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STATUS CODESSTATUS CODES Success 2xxSuccess 2xx

These codes indicate success.These codes indicate success.

No Response 204No Response 204 Server has received the request but there is no informationServer has received the request but there is no information

to send back, and the client should stay in the sameto send back, and the client should stay in the samedocument view.document view.

Error 4xx, 5xxError 4xx, 5xx The 4xx codes are intended for cases in which the clientThe 4xx codes are intended for cases in which the client

seems to have erred, and the 5xx codes for the cases inseems to have erred, and the 5xx codes for the cases inwhich the server is aware that the server has erred.which the server is aware that the server has erred.

Bad request 400Bad request 400 The request had bad syntax or was inherently impossibleThe request had bad syntax or was inherently impossible

to be satisfied.to be satisfied.

Unauthorized 401Unauthorized 401 The parameter to this message gives a specification ofThe parameter to this message gives a specification of

authorization schemes which are acceptable.authorization schemes which are acceptable.

STATUS CODESSTATUS CODES


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STATUS CODESSTATUS CODES Not found 404Not found 404

The server has not found anythingThe server has not found anythingmatching the URI given.matching the URI given.

Internal Error 500Internal Error 500 The server encountered an unexpected conditionThe server encountered an unexpected condition

which prevented it from fulfilling the request.which prevented it from fulfilling the request. Not implemented 501Not implemented 501

The server does not support the facility required.The server does not support the facility required.

Service temporarily overloaded 502Service temporarily overloaded 502 The server cannot process the request due to aThe server cannot process the request due to a

high load (whether HTTP servicing or otherhigh load (whether HTTP servicing or other

requests).requests).

HTTP PersistentHTTP Persistent


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HTTP PersistentHTTP PersistentConnectionConnection

HTTP persistent connections, also called HTTPHTTP persistent connections, also called HTTP

keep-alive, or HTTP connection reuse, is thekeep-alive, or HTTP connection reuse, is theidea of using the same TCP connection toidea of using the same TCP connection tosend and receive multiple HTTPsend and receive multiple HTTPrequests/responses, as opposed to opening arequests/responses, as opposed to opening a

new one for every single request/responsenew one for every single request/responsepair.pair.

Using persistent connections is veryUsing persistent connections is veryimportant for improving HTTP performance.important for improving HTTP performance.

In HTTP/1.1, persistent connections are theIn HTTP/1.1, persistent connections are thedefault behavior of any connection.default behavior of any connection.


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HTTP Session StateHTTP Session StateS-HTTP (Secure HTTP) is an extension to theS-HTTP (Secure HTTP) is an extension to the

Hypertext Transfer Protocol that allows theHypertext Transfer Protocol that allows thesecure exchange of files on the World Widesecure exchange of files on the World Wide

Web.Web.

Each S-HTTP file is either encrypted,Each S-HTTP file is either encrypted,contains a digital certificate, or both.contains a digital certificate, or both.

S-HTTP does not use any single encryptionS-HTTP does not use any single encryption

system.system.

SSL (Secure Socket Layer) is anotherSSL (Secure Socket Layer) is anotherprotocol for secure network communication.protocol for secure network communication.


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TCP/IP ModelTCP/IP Model

TCP/IP stands for Transmission ControlTCP/IP stands for Transmission Control

Protocol/Internet Protocol which is widelyProtocol/Internet Protocol which is widely

accepted and used communications protocol.accepted and used communications protocol.

TCP/IP has only four layers, which roughlyTCP/IP has only four layers, which roughly

correspond to groups of the OSI model.correspond to groups of the OSI model.The Internet, many internal business networksThe Internet, many internal business networks

and some home networks used TCP/IP.and some home networks used TCP/IP.

TCP (Transmission Control Protocol) responsibleTCP (Transmission Control Protocol) responsible

for reliable delivery of data.for reliable delivery of data. IP (Internet Protocol) provides addressing andIP (Internet Protocol) provides addressing and

routing information.routing information.


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TCP/IP LayersTCP/IP Layers

The four layers in TCP/IP are :The four layers in TCP/IP are : Application LayerApplication Layer

Transport LayerTransport Layer

Internet LayerInternet Layer

Network Interface LayerNetwork Interface Layer

OSI and TCP/IP Model


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TCP/IP vs. OSI

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

Application

Transport

Internet

Network Interface

OSI and TCP/IP Model


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Network Interface LayerNetwork Interface Layer Provides physical interface for transmissionProvides physical interface for transmission

of information.of information.

Covers all - mechanical, electrical, functionalCovers all - mechanical, electrical, functionaland procedural - aspects for physicaland procedural - aspects for physicalcommunication.communication.

This layer attempts to provide reliableThis layer attempts to provide reliablecommunication over the physical layercommunication over the physical layerinterface.interface.

Supports points-to-point as well as broadcastSupports points-to-point as well as broadcastcommunication.communication.

Supports simplex, half-duplex or full-duplexSupports simplex, half-duplex or full-duplexcommunicationcommunication


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Internet LayerInternet Layer

Implements routing of framesImplements routing of frames

(packets) through the network.(packets) through the network.

Defines the most optimum path theDefines the most optimum path the

packet should take from the source topacket should take from the source to

the destinationthe destinationHandles congestion in the network.Handles congestion in the network.

The network layer also defines how toThe network layer also defines how to

fragment a packet into smaller packetsfragment a packet into smaller packetsto accommodate different media.to accommodate different media.


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Transport LayerTransport Layer

Purpose of this layer is to provide aPurpose of this layer is to provide areliable mechanism for the exchange ofreliable mechanism for the exchange of

data between two processes in differentdata between two processes in different

computers.computers.

Ensures that the data units are deliveredEnsures that the data units are deliverederror free.error free.

Ensures that there is no loss orEnsures that there is no loss or

duplication of data units.duplication of data units.

Provides for the connectionProvides for the connection

management.management.

Multiplex multiple connection over aMultiplex multiple connection over a

single channel.single channel.


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Application LayerApplication Layer

Application layer interacts with applicationApplication layer interacts with application

programs and is the highest level of TCP/IPprograms and is the highest level of TCP/IP

model.model.

Application layer contains managementApplication layer contains managementfunctions to support distributedfunctions to support distributed

applications.applications.

Examples of application layer areExamples of application layer are

applications such as file transfer,applications such as file transfer,electronic mail, remote login etc.electronic mail, remote login etc.


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Issues in Intranet SecurityIssues in Intranet Security

Security through ObscuritySecurity through Obscurity

Using the Server SecurityUsing the Server Security

FirewallsFirewallsVirtual Private NetworkVirtual Private Network

Security throughSecurity through


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Security throughSecurity through

ObscurityObscurity Security through obscurity is the way to preventSecurity through obscurity is the way to prevent

casual users from accessing your Intranet is tocasual users from accessing your Intranet is tomake it hard to find.make it hard to find.

There are a few ways to hide your Intranet.There are a few ways to hide your Intranet.

Using non-standard ports - The standard port is 80.Using non-standard ports - The standard port is 80.Using a different port will make it harder to find.Using a different port will make it harder to find.

Using hard to guess names - Most companies use WWWUsing hard to guess names - Most companies use WWWfor the Web server machine name. Using somethingfor the Web server machine name. Using somethingdifferent can make it harder to find.different can make it harder to find.

Hiding your server's name - This can be done by notHiding your server's name - This can be done by notlisting it in the DNS tables for your site, and not using itlisting it in the DNS tables for your site, and not using itto browse the Web, send e-mail, or post to Usenet.to browse the Web, send e-mail, or post to Usenet.


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Using the Server SecurityUsing the Server Security

There are two security models you can use toThere are two security models you can use tosecure your Web server:secure your Web server:

Restricting by IP AddressRestricting by IP Address Almost all Web servers have an access list that definesAlmost all Web servers have an access list that defines

what machines or networks are allowed to retrievewhat machines or networks are allowed to retrievedocuments or submit forms. This access list is usuallydocuments or submit forms. This access list is usuallymade up of a list of allow and deny fields.made up of a list of allow and deny fields.

Usernames and PasswordsUsernames and Passwords When a user encounters a page that is protected, aWhen a user encounters a page that is protected, a

box appears asking for username. After the usernamebox appears asking for username. After the usernameis entered, the password is required. Once theis entered, the password is required. Once thepassword has been entered, it is checked to makepassword has been entered, it is checked to makesure it is the correct one.sure it is the correct one.


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FirewallsFirewallsFirewalls are a system or group of systemsFirewalls are a system or group of systems

that enforce a policy between twothat enforce a policy between twonetworks.networks.

In most cases one of the networks is theIn most cases one of the networks is theInternet; however, firewalls can be placedInternet; however, firewalls can be placedbetween any two networks.between any two networks.

Firewall consists of software which blocksFirewall consists of software which blocksaccess to internal network from theaccess to internal network from theInternet.Internet.

Firewalls are split into two differentFirewalls are split into two differentcategories: network-level and application-categories: network-level and application-level firewalls.level firewalls.


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Virtual Private NetworkVirtual Private Network

A VPN uses hardware or software to encryptA VPN uses hardware or software to encryptall the traffic that travels over the Internetall the traffic that travels over the Internetbetween two predetermined end-points.between two predetermined end-points.

VPN technology at present works best forVPN technology at present works best forencrypting traffic between two known pointsencrypting traffic between two known pointsthat are accepted as valid destinations forthat are accepted as valid destinations fortraffic.traffic.

Once a link is established, VPN is used toOnce a link is established, VPN is used toencrypt the information which is sent.encrypt the information which is sent.


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Future of IntranetFuture of Intranet

Corporate intranet will take an increasingCorporate intranet will take an increasingimportance as more and more businesses turn toimportance as more and more businesses turn toWeb-based applications to manage core businessWeb-based applications to manage core businesssystems like SAP and PeopleSoft.systems like SAP and PeopleSoft.

Companies are learning that on-demand WebCompanies are learning that on-demand Webservices are cheaper to maintain and easier to useservices are cheaper to maintain and easier to usethan hosting software on their own systems.than hosting software on their own systems.

All of these Web-based applications can be bundledAll of these Web-based applications can be bundledinto the corporate intranet where they can beinto the corporate intranet where they can be

accessed securely with one network password.accessed securely with one network password.

Protocols ofProtocols of


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CommunicationsCommunicationsThere are so many protocols used forThere are so many protocols used for

communications:communications: HTTPHTTP

TCP/IPTCP/IP

SMTPSMTP NNTPNNTP

FTPFTP

SOAPSOAP

UDPUDP



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CommunicationsCommunicationsSMTPSMTP

SMTP is a short for Simple Mail TransferSMTP is a short for Simple Mail Transfer

Protocol and it is used to transfer e-mailProtocol and it is used to transfer e-mail

messages between computers.messages between computers. Simple Mail Transfer Protocol is a 'push'Simple Mail Transfer Protocol is a 'push'

protocol and it cannot be used to 'pull' theprotocol and it cannot be used to 'pull' the

messages from the server.messages from the server.

SMTP is used to send the message from theSMTP is used to send the message from themail client to the mail servermail client to the mail server

NNTPNNTP


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NNTPNNTP Network News Transfer Protocol is theNetwork News Transfer Protocol is the

predominant protocol used by computerpredominant protocol used by computer

clients and servers for managing the notesclients and servers for managing the notes

posted on Usenet newsgroups.posted on Usenet newsgroups.

NNTP servers manage the global networkNNTP servers manage the global network

of collected Usenet newsgroups andof collected Usenet newsgroups andinclude the server at your Internet accessinclude the server at your Internet access

provider.provider.

An NNTP client is included as part of aAn NNTP client is included as part of a

Netscape, Internet Explorer, Opera, orNetscape, Internet Explorer, Opera, orother Web browser or you may use aother Web browser or you may use a

separate client program called aseparate client program called a

newsreadernewsreader

FTPFTP


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FTPFTP Short forShort for FFileile TTransferransferPProtocol,rotocol, thethe

protocol for exchanging files over theprotocol for exchanging files over the

Internet.Internet.

FTP uses the Internet's TCP/IP protocols toFTP uses the Internet's TCP/IP protocols to

enable data transfer.enable data transfer.

FTP is most commonly used to download aFTP is most commonly used to download afile from a server using the Internet or tofile from a server using the Internet or to

upload a file to a server (e.g., uploading aupload a file to a server (e.g., uploading a

Web page file to a server).Web page file to a server).

SOAPSOAP


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SOAPSOAP SOAP stands for Simple Object AccessSOAP stands for Simple Object Access

Protocol.Protocol.

SOAP is a communication protocolSOAP is a communication protocol

SOAP is for communication betweenSOAP is for communication betweenapplicationsapplications

SOAP is a format for sending messagesSOAP is a format for sending messages

SOAP communicates via InternetSOAP communicates via Internet

SOAP is platform independentSOAP is platform independent

SOAP is language independentSOAP is language independent

SOAP is based on XMLSOAP is based on XML SOAP is simple and extensibleSOAP is simple and extensible

SOAP allows you to get around firewallsSOAP allows you to get around firewalls

UDPUDP


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UDPUDP User Datagram Protocol or UDP is part ofUser Datagram Protocol or UDP is part of

the Internet Protocol suite, using which,the Internet Protocol suite, using which,

programs running on different computersprograms running on different computerson a network can send short messageson a network can send short messagesknown as Data grams to one another.known as Data grams to one another.

UDP can be used in networks where TCP isUDP can be used in networks where TCP is

traditionally used, but unlike TCP, it doestraditionally used, but unlike TCP, it doesnot guarantee reliability or the rightnot guarantee reliability or the rightsequencing of data.sequencing of data.

UDP is a stateless protocol which is usefulUDP is a stateless protocol which is useful

for servers engaged in answering shortfor servers engaged in answering shortqueries from a large number of clients.queries from a large number of clients.