Douglas Comer是著名的网络技术作家、教师和顾问，他对因特网的概念和工作原理有其独到的见解和清晰的认识。在本书的第4版中，Comer教授从一种非技术化的角度来解释因特网后台的工作机制。计算机的通信方式、服务器以及因特网技术的原理。作者借助实用的方法，以清晰易懂且科学准确的语言介绍了因特网的各种技术及其不同的应用，向读者展示出网络互连和因特网的全景图。

Douglas Comer是著名的网络技术作家、教师和顾问，他对因特网的概念和工作原理有其独到的见解和清晰的认识。在本书的第4版中，Comer教授从一种非技术化的角度来解释因特网后台的工作机制。计算机的通信方式、服务器以及因特网技术的原理。作者借助实用的方法，以清晰易懂且科学准确的语言介绍了因特网的各种技术及其不同的应用，向读者展示出网络互连和因特网的全景图。

Preface

Chapter1TheInternetHasArrived

TheWorldHasChanged

NumbersDoNotTellTheStory

LearningAboutTheInternet

UnderstandingTheBigPicture

TerminologyAndTechnology

GrowthAndAdaptability

TheImpactOfTheInternet

OrganizationOfTheBook

APersonalNote

Chapter2GettingStarted:Hands-OnExperience

Introduction

TheWeb:SitesAndPages

WebBrowsersandBrowsing

UsingABrowser

ExamplesOfWebSitesAndServices

InternetSearch

Summary

Chapter3TelephonesEverywhere

Introduction

ACommunicationService

SellingCommunication

LimitedAccess

HighCost

TheDifficultTransition

UbiquitousAccess

RelevanceToTheInternet

Chapter4TheWorldWasOnceAnalog

Introduction

Sound,Vibrations,AndAnalogRecording

AnalogElectronicDevices

ManyElectronicDevicesAreAnalog

TheFirstAnalogCommunication

AnalogIsSimpleButInaccurate

SendingAnAnalogSignalAcrossAWire

DigitalMusic

TheDigitalRevolution

ComputersAreDigital

DigitalRecording

UsingDigitalToRecreateAnalog

WhyDigitalMusic?

Summary

Chapter5TheOnceAndFutureDigitalNetwork

Introduction

TheWorldWasPreviouslyDigital

ATelegraphIsDigital

MorseCode

LettersAndDigitsInMorseCode

UsersDidNotEncounterMorseCode

VirtuallyInstantCommunication

SpeedIsRelative

TheTelephoneBecameDigital

RelevanceToTheInternet

BinaryEncodingOfDataOnTheInternet

WhyUseTwoSymbols?

Summary

Chapter6BasicCommunication

Introduction

CommunicationUsingElectricity

SignalsOnWires

InformationCoding

ModemsAllowTwo-WayTraffic

ACharacterCodeForDigitalInformation

DetectingErrors

Summary

Chapter7TheLocalAreaNetworkArrives

Introduction

Motivation

InterchangeableMedia

AComputerConsistsOfCircuitBoards

CircuitBoardsPlugIntoAComputer

ConnectingOneComputerToAnother

LANTechnologies

ConnectingAComputerToALAN

TheImportanceOfLANTechnology

RelationshipToTheInternet

PARTIIABriefHistoryOfTheInternet

Chapter8Internet:TheEarlyYears

ManyIndependentNetworks

TheProliferationOfLANs

FactsAboutLANs

LANsAreIncompatible

WideAreaTechnologiesExist

FewWANs,ManyLANs

WANsandLANsAreIncompatible

TheDesirabilityOfASingleNetwork

TheDepartmentOfDefenseHadMultipleNetworks

ConnectingDisconnectedMachines

TheInternetEmerges

TheARPANETBackbone

InternetSoftware

TheNameIsTCP/IP

TheShockOfAnOpenSystem

OpenSystemsAreNecessary

TCP/IPDocumentationIsOnline

TheMilitaryAdoptsTCP/IP

Summary

APersonalNote

Chapter9TwoDecadesOfIncredibleGrowth

Introduction

DisseminatingTheSoftware

Meanwhile,BackInComputerScience

TheInternetMeetsUNIX

TheU.S.MilitaryMakesACommitment

TheInternetDoublesInSizeInOneYear

EveryComputerScienceDepartment

GraduateStudentsVolunteerTheirTime

TheIABevolves

TheIETF

DoublingAgainInAYear

TheInternetImprovesScience

NSFTakesALeadershipRole

Target:AllOfScienceAndEngineering

NSF’sApproach

TheNSFNETBackbone

TheANSBackbone

ExponentialGrowth

ACommercialAssessment

TheEndOfGrowth

Chapter10TheGlobalInternet

Introduction

EarlyARPANetwos

ElectronicMailAmngComputers

BITNETAndFIDONET

NetworksInEurope

EBONE:TheInternetInEurope

BackbonesAndInternetHierarchy

InternetOnAllContinents

TheWorldOfInternetafter1998

APersonalNote

Chapter11AGlobalInformationInfrastructure

Introduction

ExistingInfrastructure

CommunicationInfrastructure

TheInternetInfrastructure

TheInternetOffersDiverseInformationServices

TCP/IPProvidesCommunicationFacilities

APersonalNote

PARTIIIHowTheInternetWorks

Chapter12PacketSwitching

Introduction

SharingSavesMoney

SharingIntroducesDelays

SharingWires

SelectableChannels

SharingByTakingTurns

PacketSwitchingAvoidsDelays

EachPacketMustBeLabeled

ComputersHaveAddresses

PacketsAreNotAllTheSameSize

PacketTransmissionSeemsInstantaneous

SharingIsAutomatic

NetworkHardwareHandlesSharing

ManyDevicesCanUsePacketSwitching

RelevanceToTheInternet

Summary

Chapter13Internet:ANetworkOfNetworks

Introduction

NetworkTechnologiesAreIncompatible

CopingWithIncompatibility

TwoFundamentalConcepts

UsingAComputerToInterconnectNetworks

InterconnectingComputersPassPackets

InterconnectingComputersAreCalledRouters

RoutersAreTheBuildingBlocksOfTheInternet

TheInternetIncludesMultipleTypesOfNetworks

RoutersCanInterconnectWANsAndLANs

TheHierarchicalStructureOfTheInternet

WherePacketsTravel

InterconnectingNetworksWasRevolutionary

Summary

Chapter14ISPs:BroadbandAndWirelessAccess

Introduction

InternetServiceProvidersAndFees

CustomerConnectionsFormTheLastMile

LeasedCircuitsAreExpensive

Dial-upAccessIsInexpensive,ButSlow

BroadbandConnectionsOfferHighSpeed

TheImportantConceptOfContinuousConnectivity

InstantaneousAccessChangesUse

ModernTechnologiesOfferInexpensiveDedicatedAccess

WirelessAccessIsAvailable

Wi-FiAnd3GWirelessTechnologies

APersonalNote

Chapter15IP:SoftwareToCreateAVirtualNetwork

Introduction

Protocol:AnAgreementForCommunication

BasicFunctionality:TheInternetProtocol

IPSoftwareOnEveryMachine

InternetPacketsAreCalledDatagrams

TheIllusionOfAGiantNetwork

TheInternet’sInternalStructure

DatagramsTravelInPackets

EveryComputerIsAssignedAUniqueAddress

InternetAddresses

AnOddIPAddressSyntax

IPAddressesAreNotRandom

ATripThroughAnExampleInternet

HowFastIsYourConnection?

Summary

Chapter16TCP:SoftwareForReliableCommunication

Introduction

APacketSwitchingSystemCanBeOverrun

TCPHelpsIPGuaranteeDelivery

TCPProvidesAConnectionBetweenComputerPrograms

TheMagicOfRecoveringLostDatagrams

TCPRetransmissionIsAutomatic

TCPAndIPWorkTogether

Summary

Chapter17Clients+Servers=DistributedComputing

Introduction

LargeComputersUseNetworksForInputAndOutput

SmallComputersUseNetworksToInteract

DistributedComputingOnTheInternet

ASingleParadigmExplainsAllDistributedComputing

CommunicatingProgramsAreClientsOrServers

AServerMustAlwaysRun

Summary

Chapter18NamesForComputers

Introduction

PeoplePreferNamesToNumbers

NamingAComputerCanBeChallengingOrFun

ComputerNamesMustBeUnique

SuffixesOnComputerNames

NamesWithManyParts

DomainNamesOutsideTheUS

TranslatingANameToAnEquivalentIPAddress

DomainNameSystemWorksLikeDirectoryAssistance

ComputerNameLookupIsAutomatic

IPAddressesAndDomainNamesAreUnrelated

Summary

Chapter19NAT:SharingAnInternetConnection

Introduction

HighCapacityAndMultipleComputers

ItIsPossibleToShareASingleIPAddress

ADeviceForConnectionSharingIsCalledANATBox..

ANATBoxActsLikeAMiniatureISP

NATChangesTheAddressInEachDatagram

ComputerSoftwareCanPerformTheNATFunction

NATCanUseAWirelessNetwork

Summary

Chapter20WhyTheInternetWorksWell

Introduction

TheInternetWorksWell

IPProvidesFlexibility

TCPProvidesReliability

TCP/IPSoftwareWasEngineeredForEfficiency

TCP/IPResearchEmphasizedPracticalResults

TheFormulaForSuccess

Summary

PARTIVServicesAvailableOnTheInternet

Chapter21ElectronicMail

Introduction

DescriptionOfFunctionality

TheBestOfAllWorlds

EachUserHasAMailboxForEmail

SendingAnEmailMessage

NotificationThatEmailHasArrived

ReadingAnEmailMessage

ABrowserCanBeUsedToSendAndReceiveEmail

EmailMessagesLookLikeInterofficeMemos

EmailSoftwareFillsInHeaderInformation

HowEmailWorks

UsingEmailFromAPersonalComputer

MailboxAddressFormat

AbbreviationsMakeEmailFriendly

AliasesPermitArbitraryAbbreviations

AliasesSharedByAllUsersOfAComputerSystem

SendingToMultipleRecipients

MailingList:AnAliasforMultipleRecipients

PublicMailingListsAndMailExploders

ExchangingEmailWithNon-InternetSites

AccessToServicesViaEmail

Speed,Reliability,AndExpectations

ImpactAndSignificanceOfElectronicMail

AConventionForJoiningAMailingList

Chapter22BulletinBoardService(Newsgroups)

Introduction

DescriptionOfFunctionality

ManyBulletinBoardsWithDiverseTopics

NetworkNews

Categories

ObtainingNetworkNewsAndTheSoftwareToReadArticles

HowNetworkNewsAppearsToAUser

CheckingForNewsArticles

ReadingNetworkNews

SubmissionOfAnArticle

ModeratedNewsgroups

SizeOfNetworkNews

ImpactAndSignificanceOfNewsgroupsAndMailingLists

HintsAndConventionsForParticipatingInDiscussions

Summary

Chapter23BrowsingTheWorldWideWeb

Introduction

DescriptionOfFunctionality

BrowsingVs.InformationRetrieval

EarlyBrowsingServicesUsedMenus

AMenuItemCanPointToAnotherComputer

HowABrowserWorks

AnExamplePoint-And-ClickInterface

CombiningMenuItemsWithText

TheImportanceOfIntegratedLinks

EmbeddedLinksInTextAreCalledHypertext

Multimedia

VideoAndAudioReferencesCanBeEmbeddedInText

TheWorldWideWeb

BrowserSoftwareUsedToAccessTheWeb

AnExampleHypermediaDisplay

ControlOfABrowser

ExternalReferences

RecordingTheLocationOfInformation

BookmarksOrFavorites

HowTheWorldWideWebWorks

AURLTellsABrowserWhichComputerToContact

AURLTellsABrowserWhichServerToContact

UseOfTheNamewwwInURLs

ABrowserProvidesAccessToMultipleServices

InsideABrowserProgram

Summary

AnObservationAboutHypermediaBrowsing

Chapter24WorldWideWebDocuments(HTML)

Introduction

DisplayHardwareVaries

ABrowserTranslatesAndDisplaysAWebDocument

AConsequenceOfTheWebApproach

HTML,TheLanguageUsedForWebDocuments

InstructionsInAWebPageControlTheOutput

AWebPageIsDividedIntoTwoMainSections

IndentationCanMakeHTMLReadable

TheBodyOfAWebPageCanContainText

IndentationCanMakeParagraphsEasierToFind

AWebPageCanLinkToAnotherPage

HTMLAllowsNumberedAndUnnumberedLists

ImagesOnAWebPageAreDigital

HTMLAllowsAWebPageToIncludeAnImage

TextCanAppearAdjacentToAnImage

ImagesCanLinkToAnotherWebPage

SomeBrowsersCanStretchOrShrinkImages

TheBackgroundCanBeControlled

OtherFeaturesOfHTML

ImportanceOfHTML

GUIToolsHelpWithWebPageCreation

Summary

Chapter25AdvancedWebTechnologies(Forms,Frames,Plugins,Java,JavaScript,Flash)

Introduction

ConventionalWebPagesAreStatic

HowAServerStoresStaticWebPages

FetchingItemsOneAtATime

ConventionalWebPagesUseTheEntireScreen

AWebPageCanChangePartOftheScreen

TheWeb,Advertising,AndFrames

Pop-UpsAndPop-UpBlockers

StaticDocumentsHaveDisadvantages

ControllingHowABrowserProcessesData

PluginsAllowVariety

AServerCanComputeAWebPageOnDemand

HowServer-SideScriptingWorks

ProfessionalProgrammersBuildServerScripts

PersonalizedWebPages

PersonalizedAdvertisements

WebPagesCanInteract

ShoppingCarts

Cookies

ShouldYouAcceptCookies?

AWebPageCanDisplaySimpleAnimations

ActiveDocumentsAreMorePowerful

JavaIsAnActiveDocumentTechnology

JavaScriptIsAnActiveDocumentTechnology

FlashAndRealTechnologies

TheImportanceOfAdvancedWebTechnologies

Chapter26GroupAndPersonalWebPages(WikisAndBlogs)

Introduction

TheDisadvantageOfABulletinBoardSystem

SharedPages

SharedPagesAreCalledWikis

SharingAndConsensusBuilding

TheDisadvantageOfWikis

WikipediaIsAnExperiment

ShouldYouTrustWikipedia?

PublicationOfAPersonalDiary

APersonalNote

Chapter27AutomatedWebSearch(SearchEngines)

Introduction

DescriptionOfFunctionality

BrowsingVs.AutomatedSearching

ASearchEngineHelpsUsersGetStarted

ASearchToolCanHelpRecoverFromLoss

HowAnAutomatedSearchServiceOperates

GatheringInformationInAdvance

ModernSystemsSearchWebPageContents

HowAWebSearchAppearsToAUser

HowASearchEngineReturnsResults

AutomatedSearchServicesUseStringMatching

TheAdvantagesAndDisadvantagesOfStringMatching

AutomatedSearchProgramsThatUseMultipleKeys

AdvancedServicesOfferMoreSophisticatedMatching

PersonalizedSearchResults

MoreDetailsAboutHowContentSearchingWorks

SearchesAreRestricted

AdvertisingPaysForSearching

ExamplesOfAutomatedSearchServices

SignificanceOfAutomatedWebSearch

Chapter28Text,Audio,AndVideoCommunication(IM,VoIP)

Introduction

InstantMessagingProvidesTextualCommunication

AudioAndVideoFunctionality

AudioAndVideoRequireSpecialFacilities

AnAudioClipResemblesAnAudioCD

Real-TimeMeansNoDelay

InternetAudioInReal-Time

RadioProgramsOnTheInternet

Real-TimeAudioTransmissionIsCalledWebcasting

InternetTelephoneServiceIsPossible

InternetTelephoneServiceIsKnownAsVoIP

AudioTeleconferencing

ACooperativeDocumentMarkupService

MarkingADocument

TheParticipantsDiscussAndMarkADocument

VideoTeleconferencing

VideoTeleconferenceAmongGroupsOfPeople

ACombinedAudio,Video,Whiteboard,AndIMService

Summary

APersonalNote

Chapter29Faxes,FileTransfer,AndFileSharing(FTP)

Introduction

SendingAFax

TheInternetCanBeUsedToCopyFiles

DataStoredInFiles

CopyingAFile

FTPIsInvokedFromABrowser

FTPAllowsAUserToViewDirectoryContents

FTPAllowsAUserToUploadFiles

FTPTransfersMustBeAuthorized

HowFTPWorks

ImpactAndSignificanceOfFTP

Peer-To-PeerFileSharing

Summary

Chapter30RemoteLoginAndRemoteDesktops(TELNET)

Introduction

EarlyComputersUsedTextualInterfaces

ATimesharingSystemRequiresUserIdentification

RemoteLoginResemblesConventionalLogin

HowRemoteLoginWorks

EscapingFromRemoteLogin

TheInternetRemoteLoginStandardIsTELNET

RemoteAccessCanDisplayADesktop

HowRemoteDesktopsOperate

AssessmentOfRemoteLoginAndDesktops

GeneralityMakesRemoteLoginAndDesktopsPowerful

RemoteAccessAccommodatesMultipleTypesOfComputers

UnexpectedResultsFromRemoteAccess

Summary

Chapter31FacilitiesForSecureCommunication

Introduction

TheInternetIsUnsecure

LackOfSecurityCanBeImportant

AuthenticationAndPrivacyArePrimaryProblems

DataCanBeChanged

EncodingKeepsMessagesPrivate

ComputerEncryptionUsesMathematics

NoNetworkIsAbsolutelySecure

EncryptionMakesEmailPrivate

EncryptionSoftwareNeedsAKey

TwoKeysMeansNeverHavingToTrustAnyone

SecureEmailInPractice

SecureWirelessNetworks

FirewallsProtectNetworksFromUnwantedPackets

AFirewallFiltersPackets

FirewallsGuardAgainstTrojanHorses

ResidentialAndIndividualFirewalls

SystemsExistToDetectIntrusion

ServiceCanBeDenied

Summary

Chapter32SecureAccessFromADistance(VPNs)

Introduction

OrganizationsGrantEmployeesSpecialPrivileges

TravelingEmployeesLosePrivilege

TelecommutersDoNotHavePrivilege

DedicatedLeasedCircuitsAllowSecureTelecommuting

StandardInternetConnectionsAreLow-Cost

CanATechnologyCombineAdvantages?

AVirtualPrivateNetworkSolvesTheProblem

HowAVPNWorks

TheIllusionOfADirectConnection

SignificanceOfVPNs

Chapter33InternetEconomicsAndElectronicCommerce

Introduction

WhoPaysForTheInternet?

E-commerceIsBigBusiness

SecurityTechnologyMadeE-commercePossible

SecureSockets

PublicKeyEncryptionProvidesAuthenticity

DigitalSignatures

CertificatesContainPublicKeys

WhatIsDigitalMoney?

DigitalCashIsNotWidelyAvailable

BusinessAndE-commerce

TheControversiesOverTaxationAndNetNeutrality

Chapter34TheGlobalDigitalLibrary

Introduction

ACornucopiaOfServices

NewServicesAppearRegularly

FlexibilityPermitsChange

ADigitalLibrary

CardCatalogsAndSearchTools

InternetServicesCanBeIntegrated

Mr.Dewey,WhereAreYou?

InformationInTheDigitalLibrary

WhatIsTheInternet?

Appendix1GlossaryOfInternetTerms

Index