Learn Components of IPv4 Header Format - eduCBA

IPv4 Header Format Component · Version: The first header field is a 4-bit version indicator. · Internet Header Length: IHL is the 2nd field of an IPv4 header, and ... IPv4HeaderFormat ByPriyaPedamkar Home»SoftwareDevelopment»SoftwareDevelopmentTutorials»NetworkSecurityTutorial»IPv4HeaderFormat OverviewofIPv4HeaderFormat IPV4headerformatisof 20to60bytesinlength,containsinformationessentialtoroutinganddelivery,consistof13fields,VER,HLEN,servicetype,totallength,identification,flags,fragmentationoffset,timetolive,protocol,headerchecksum,sourceIPaddress,DestinationIPaddressandoption+padding,whereeachhasitsownfeaturesandprovidesessentialdatarequiredtotransmitthedata. StartYourFreeSoftwareDevelopmentCourse Webdevelopment,programminglanguages,Softwaretesting&others AnIPv4packetheaderhasatotalof14fields;amongthese14fields,onlyoneisoptional,whichisaptlyknownastheoptionscomponent. IPv4HeaderFormatComponent Belowisthelistmentioned. Version. InternetHeaderLength. TypeofService. ExplicitCongestionNotification. TotalLength. Identification. Flags. FragmentOffset Timetolive. Protocol. Achecksumofheader. SourceAddress. DestinationAddress. Options. Let’stakealookatthesecomponents,theirsizesandwhattheycando: Version:Thefirstheaderfieldisa4-bitversionindicator.InthecaseofIPv4,thevalueofitsfourbitsissetto0100,whichindicates4inbinary. InternetHeaderLength: IHListhe2ndfieldofanIPv4header,anditisof4bitsinsize.Thisheadercomponentisusedtoshowhowmany32-bitwordsarepresentintheheader.Asweknow,IPv4headershaveavariablesize,sothisisusedtospecifythesizeoftheheadertoavoidanyerrors.Thissizecanbebetween20bytesto60bytes. TypeofService:ToSisalsocalledDifferentiatedServicesCodePointorDSCP.Thisfieldisusedtoprovidefeaturesrelatedtoservicequality,suchasfordatastreamingorVoiceoverIP(VoIP)calls.Itisusedtospecifichowadatagramwillbehandled. ExplicitCongestionNotification:ECNisusedtosendnotificationstothesenderorreceiveinsituationswherenetworkcongestionhappens.ThisisanoptionalfeatureofIPv4can;ifoneoftheendpointsdon’tsupportit,itisnotused. TotalLength:Thisfield’ssizeis16bit,anditisusedtodenotethesizeoftheentiredatagram.TheminimumsizeofanIPdatagramis20bytes,andatthemaximum,itcanbe65,535bytes.Practically,allhostsarerequiredtobeabletoread576-bytedatagrams.Ifadatagramistoolargeforthehostsinthenetwork,fragmentationisused,whichishandledinthehostorpacketswitch. Identification:TheidentificationorIDfieldinapacketcanidentifyanIPdatagram’sfragmentsuniquely.Somehavesuggestedusingthisfieldforotherthingssuchasaddinginformationforpackettracingetc. Flags:flaginanIPv4headerisathree-bitfieldthatisusedtocontrolandidentifyfragments.Thefollowingcanbetheirpossibleconfiguration: Bit0:thisisreservedandhastobesettozero Bit1:DFordonotfragment Bit2:MFormorefragments. FragmentOffset:Thisfieldis13bitlonginlength,anditismeasuredbyblocksthatunitsof8-byteblocks.TheseareusedtospecifytheoffsetofafragmentrelativetothestartoftheIPdatagram,whichwhenitwasnotfragmented.Asyoucanexpect,thefirstoffsetofafragmentisalwayssettozero.Themaximumpossibleoffsetis(213-1)*8=65528,butitismorethanthemaximumpossibleIPPacketlength,whichis65,535byteslongwiththelengthofaheaderaddedin. Timetolive:Timetolive(orTTLinshort)isan8-bitfieldtoindicatethemaximumtimethedatagramwillbeliveintheinternetsystem.Thetimehereismeasuredinseconds,andincasethevalueofTTLiszero,thedatagramiserased.Everytimeadatagramisprocessed,it’sTimetoliveisdecreasedbyonesecond.Theseareusedsothatdatagramsthatarenotdeliveredarediscardedautomatically.TTLcanbebetween0–255. Protocol:ThisisafiledintheIPv4headerreservedtodenotewhichprotocolisusedinthelater(data)portionofthedatagram.ForExample,number6isusedtodenoteTCPand17isusedtodenoteUDPprotocol. Theheader’schecksum:Thechecksumfieldisof16-bitlength,anditisusedtochecktheheaderforanyerrors.Theheaderiscomparedtothevalueofitschecksumateachhop,andincasetheheaderchecksumisnotmatching,thepacketisdiscarded.Keepinmindthatthisisonlyfortheheader,anditsprotocolhandlesthedatafield.UDPandTCP,forexample,havetheirownchecksumfields. SourceAddress: Itisa32-bitaddressofthesourceoftheIPv4packet. DestinationAddress:thedestinationaddressisalso32bitinsize,anditcontainsthereceiver’saddress. Options:ThisisanoptionalfieldoftheIPv4header.ItisusedonlywhenthevalueofIHLissettomorethan5.Theseoptionscontainvaluesandsettingsforthingsrelatedtosecurity.Recordrouteandtimestampetc.YouwillfindthatthelistofoptionscomponentendswithanEndofOptionsorEOLinmanycases. Conclusion IPheadersareoneofthecrucialcomponentsoftheprotocol.Beingabletotellthenetworkaboutthedatagram,itssource,anditsdestinationisimportant,andsoistheabilitytodetectanyerrorsintheheadertoavoidusingcorruptedpackets.ConsideringthatalmostallofthemoderninternetreliesonIPv4andIPv6,theseheadersareusedinalmostalloftheHTTPinternettraffic. RecommendedArticles ThishasbeenaguidetoIPv4HeaderFormat.HerewediscussedIntroductiontoIPv4HeaderFormat,itscomponentswiththeirsizesandwhattheyareusedfor.Youcanalsogothroughourothersuggestedarticlestolearnmore– NetworkingInterviewQuestions ComputerHardwarevsNetworking WhatisIPv6? WhatisIPv4? CyberSecurityTraining(12Courses,3Projects) 10OnlineCourses 3Hands-onProjects 65+Hours VerifiableCertificateofCompletion LifetimeAccess LearnMore 1SharesShareTweetShare PrimarySidebar NetworkSecurityTutorial Advanced Cryptosystems ConfiguringDHCPServer EncapsulationSecurityPayload BlockCiphermodesofOperation TCP/IPModel Adhocnetworktypes TypesofNetwork TypesofNetworkDevices TypesofNetworkTopology TypesofIntrusionPreventionSystem TypesofProxyServers TypesofWebsites TypesofNAT MobileIP CareerinAutomobileDesign WhatisTFS WhatisNAT WhatisOSIModel DataLinkLayerOSIModel WhatisCrossSiteScripting ApplicationsofSensors ARPPacketFormat WhatisPacketSwitching? PacketSwitchingAdvantages AsymmetricInformation Autoencoders WhatisFTPServer? IPSTools OpenSSLtool IPv4HeaderFormat IPv6HeaderFormat AuthenticationHeader AuthenticationTypes Kerberos NetworkMapper NetworkScanningTools NetworkMappingTools NetworkAccessControl VulnerabilityAssessmentTools NetworkSniffer NetworkingCommands NetworkingDevices NetworkingStrategies DigitalCertificate WhatisaDigitalSignature? DigitalSignatureSoftwares DigitalSignatureTypes DigitalSignaturevsDigitalCertificate PKCS Ethernetuses HTTPUses ServletSessionManagement WhatisFTP FTPCommands WhatisMIME? WhatisSmartCard? NetworkingPorts MutualAuthentication PasswordAuthentication DataMasking AuthenticationTokens BiometricAuthentication WhatisIP? IPSec SecureElectronicTransaction WhatisCIDR StaticBindingandDynamicBinding WhatisSSL PKIX PublicKeyInfrastructure WhatisWireshark UseofWireshark DaisyChainTopology MarkovLogicNetwork Securityengineering SNMPMonitoringTools NetworkAnalysisTools ServerMonitoringTools NetworkDiscoveryTools NetworkManagementTool SIEMTools OSINTTools MultiplePingTool Basics SecurityConsultantDefinition SecurityPolicies WhatisNetworkSecurity WhatisDataSecurity? WhatisCryptography CryptographyTechniques CryptographyTools DataSecurityTechniquesandPrivacy Phishing?Tools Ransomwaredecryptiontools OpenSSH AuthorizationTypes DigitalSignatureCryptography JavaCryptography BasicsofCybersecurity WhatisNetworkTopology AlgorithmsandCryptography HTTPMethods Authenticationmethods SecurityTechnologies SecurityArchitecture EmailSecurityGateways NetworkMonitoringTools NetworkAnalysis TypesofddosAttack NetworkTopologies WhatisaPhysicalAddress? PacketSwitchingAdvantagesandDisadvantages LogicalAddress WhatisStorageAreaNetwork? MobileAdHocNetwork WhatisComputerNetworks? SecurityPrinciples DataIntegrity SubnettingandSupernetting WhatisRemoteAccess? OpenSSLVersion OpenSSHversion PortForwarding PrivilegedAccessManagementTools SecurityTestingTypes Protocols WhatisTCPProtocol WhatisTCP/IP HowdoIPAddressesWork? POPProtocol CentOSChangeIPAddress IPSecprotocol Applicationlayerprotocols DataLinkLayerProtocol RoutingProtocolsTypes SpoofingTypes WhatisTelnet WhatisTFTP WhatisDHCP DHCPAdvantages WhatisSFTP AddressResolutionProtocol ISAKMPProtocol InternetControlMessageProtocol SimpleMailTransferProtocol InternetSecurityProtocols RIPProtocol SMTPProtocol TypesofNetworkingProtocols UserDatagramProtocol DataLinkLayer DataLinkLayerServices NetworkLayer TransportLayerProtocols WhatIsNetworkingProtocols TFTP WhatisARP BasicFundamentalOfNetworking WhatisIPv4 WhatisIPv6 CIFSProtocol WhatisSMB? WhatisSIEM WhatisSubnet? PortForwardingSoftware OSPFRouterTypes WhatisEIGRP WhatisLLDP? Routing WhatisRouter TypesofRouters DynamicRouting RoutingAlgorithms RoutingProtocol WhatisRouting WhatisStaticRouting ImportantTypesofDNSServers(Powerful) Attacks TypesofNetworkAttacks WhatisTrojanHorseVirus WhatisDOS TypesofDOSAttacks DDosAttackMitigation RansomwareAttack TypesofCyberAttack WhatisaBruteForceAttack WhatisaPhishingAttack WhatisCyberAttack WhatisDDoSAttack WhatisManInTheMiddleAttack WhatisManInTheMiddleAttack WhatisRansomware WhatisPharming WhatisPhishing WhatisCSRF DNSAmplificationAttack DenialofServiceAttack Algorithm IDEAAlgorithm MD5Algorithm SymmetricAlgorithms DiffieHellmanKeyExchangeAlgorithm DigitalSignatureAlgorithm EncryptionAlgorithm AdvancedEncryptionStandard AsymmetricEncryption ElGamalEncryption HMAC DESAlgorithm BruteForceAlgorithm SHAAlgorithm RSAAlgorithm WhatisDigitalCertificate? CertificateRevocation RC5 Encryption/Decryption Encryptionprocess PublicKeyEncryption SymmetricKeyEncryption WhatisEncryption WhatisDecryption TypesofCipher TranspositionTechniques WhatisSteganography OneTimePad SteganographyTechniques Hosting TypesofWebHosting WebDocuments FreeWebHostingSites WhatisHosting WhatisVPSHosting WhatisWebHosting TypesofDomain VPNApplicationsforPC WhyweuseVPN? VPNTunneling WhatisVirtualHost? Firewalls WhatisaFirewall? TypesofFirewalls FirewallDevices FirewallSecurity FirewallUses InterviewQuestions NetworkSecurityInterviewQuestions NetworkingInterviewQuestions EIGRPInterviewQuestions RelatedCourses CDNTrainingOSPFCertificationTrainingPenetrationTrainingCourse Loading... Question: Answer: QuizResultTotalQuestionsCorrectAnswersWrongAnswersPercentage Explore1000+varietiesofMocktestsViewmore SubmitNextQuestion X FreeSoftwareDevelopmentCourseWebdevelopment,programminglanguages,Softwaretesting&others *Pleaseprovideyourcorrectemailid.LogindetailsforthisFreecoursewillbeemailedtoyouBysigningup,youagreetoourTermsofUseandPrivacyPolicy. x EDUCBALoginUsername PasswordForgotPassword? SubmitBysigningup,youagreetoourTermsofUseandPrivacyPolicy. X BookYourOneInstructor:OneLearnerFreeClass Name: EmailID ContactNo. x x Let’sGetStarted EmailID* Bysigningup,youagreetoourTermsofUseandPrivacyPolicy. X Thiswebsiteoritsthird-partytoolsusecookies,whicharenecessarytoitsfunctioningandrequiredtoachievethepurposesillustratedinthecookiepolicy.Byclosingthisbanner,scrollingthispage,clickingalinkorcontinuingtobrowseotherwise,youagreetoourPrivacyPolicy OK x *Pleaseprovideyourcorrectemailid.LogindetailsforthisFreecoursewillbeemailedtoyouBysigningup,youagreetoourTermsofUseandPrivacyPolicy. X FreeSoftwareDevelopmentCourse Webdevelopment,programminglanguages,Softwaretesting&others *Pleaseprovideyourcorrectemailid.LogindetailsforthisFreecoursewillbeemailedtoyouBysigningup,youagreetoourTermsofUseandPrivacyPolicy. X SpecialOffer-CyberSecurityTraining(12Courses,3Projects)LearnMore