Linux oӧ@~tΪ̤juմNOb\ ( Network ) աIo]tLíwרtθ귽tAHθwƯOIҥHܦhHwLӶiA[]CMӡAoǺ\઺uIoPɤ]OIA򻡩OH] Linux \ӱjFAҥH@Q Cracker (ǫ) JIܡAKKKKIYWxqDIҥHoAWeAХ`NGyڪnw@FܡHzA̡Aѩ Linux ]wWq`ϥΪ̤ݭnOh@IߤOALOѤ@su{vѩ󥻨ӳ]pXӪAҥH¨㦳۷·Ъ]wu@ݭn@IoӮɭԡApGS¦ ¦ {ܡAb Linux W]wΪ̬OiNOz@ͷ̤jL......AҥHAo̦XƱnбznnӰѦҤ@UG
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• x Linux ާ@P Linux ¦G٬On@Aa_jաApGzTwzuOQny|ϥ Linux Nnz@ϥΪ̡AunAUݤFA]D򪺺@D|ܤjAˤpӤpAЭӱMazdwYiIӦpGzTwzOyQnA Linux ϥΪ̡AåBQnx[]zAФnAbW߰ݡGyڤϥ FTP ǰeƨDWHzΪ̬Oyڤإ߭ӤHz̰DA]oȶȲoAyɮvPݩzӤwAӳoǷO Linux ¦Y۷n\ҡI~Aѩ󻷺ݾޱ Linux DɡAXGOϥΤrɭӤu@AҥHA bash shell HIQnFXiI
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• XߪɶN¦ݤ@Go@ӳ`b޾ɺsAHֳtiJ@ɡAҥHgL@ǨǡA򥻤WA٦@wPqTwèSQ]tboguYCpGzDwgL`AЦۦѧMAXzۤvyӾ\ŪIMAz]iHbںWzһݭnơAҦp Study Area NO@ӫܦn¦JGhttp://www.study-area.org/network/network.htmAרO IP ¦@gGhttp://www.study-area.org/network/network_ipadd.htmA۷AXJŷsѦҤΡIϥALצpAbiA[]eAzn Network @w{աI
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• HɴxDTG oO̳·Ъ@IFI]ja٬O``{yڪopASH|`NաIzILYzFANO]oؤ߲zsbAڭ̤~|``ťy_ǡIڦbWw˧AUȴNLkH root nJFIzHɪ`NzDTAnnR@LaI
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ϥLצpA׬O Linux ٬O Windows AAAѺ¦iJA[]Ĥ@ҡAU峹ЦnnACCŪI󥼨ӪDz߬OܦUI
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OG
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OOH²檺AunOⳡHWqAzLuΪ̬OLC(ҦpLudBMuBCablelu)sb@_AHiɮ׶ǿBTǻ\ANΦ@ӡy@ɡzաISjpOH򥻤WApGzObzsǤXqAΪ̬OjӤҦXʳqs_ӪANiH@Ӥpϰ ( Local Area Network, LAN, ]½Ķyz )AzL LAN AAҦpӫΰaANiHٰs ( Wide Area Network, WAN ) AӳoǵLƭӪ LAN P WAN sb@_ANOں ( Internet ) աIziHQA Internet ȬONҦ LAN P WAN sb@_@ӤAҥHAa𫍧qAunsW Internet ANSӤjtFA]NOAbayt@ݪqAPbzǪqAb Internet WAƹWOthI(uLyqINOF ^_^)I~Aݭn`NOA Internet èSMHb@AҥHLOSkaAziHb Internet Wi󪺨ƱIzInܥiȪˤlIOo˨SI Internet TOy۷iȡIz ^_^ANO]ӥiȤFAҥHڭ̱onӲ@¦rI
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\G
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nFAҿת@I{ѤAnӽͤ@͡G\OHFAuOܤ`ͬƪ@uFIIҦpzϥΪqW WWW hsɡAϥΪNO\FFzqyWھFzɪɮסBLANO\ध@FWUnAϥΪ FTP ]O\ध@IIͬƤFaIڷQAثeͬAHh_ݤ@ݩ_YɷsDaIH٦ѲաBqlTlաBרO{bܦhHysѪ𪺽uWsuCAzInh\IoOzFIMաI\Ӥ󦹡AziHA`JsI
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@B@y{G
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nաANOXqsb@_AåBiH۶iƻPTεwP(ҦpɦLLHϥ)@өNNALiHF쪺\۷hAOo̴NoAXӤF@ӰDANOyOpB@OHz²檺ANOڭ̳sW Internet ɡAƬOpǻOHUڭ̥Hثe̱` ADSL pynFCzݭnsuɡAzqDNnG
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1. dPuGb@ɸ̡Auu@ӴNOqlTաIӳoǹqlTݭnǥѵw鳘CӶǿAoNO̩hwաIڭ̳o̬OH ADSL Ӷi满AM٦ҿת֡BLuCLצpAns Internet WhAANOnysCzAoӴCbثe̱`NO RJ-45 YuPdաIMաAC@شC鳣WPtqAҥHܪɭԴNݭnh[poI

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2. 䴩C骺@~tGٰOoڭ̦b Linux ¦̭쪺 Linux kernel ܡHSIŦwAO@~tή֤ߤ䴩A]O^LΪZaաIҥHAFC𫗪AٻݭniHC鷾q@~tΨӾޱw~IثeDy@~t Windows P Linux 䴩@j諸COI

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3. Xk}GNP@ˡApGąSPAzl]qpeFۤva̡Hثe Internet Dn٬OH IPv4 oӨw IP @}зǡAںu|{o IP I~AnNƥTL~eF IP NݭnҿתyСz~AoӸƶǿ骺дNOڭ̩ҿתy, routezI

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4. ƶǿ骺kGnFA{bw鳣SDFAۤUӴNOݭnAѡyڪƬOǰeXhHIzzIn·СA٭nzѸơyʥ]zNNrII򥻤WAξߡAثewgڭ̩wqnܦhwFIҥHڭ̥unAѥL@ǰ¦zYiILNݭnӾ߰աII
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ҥHA²檺AzQns Internet WơANݭndBåBwˤFXA@~tΡAٱonXʺd~IMAϥ ADSL z ISP hoXk IP }Ao˴NiHsWƤFCOKIOKIڭ̨Ӱ]@ӪAnFApGzns _sD ܡAzO˨oWƪOH
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1. Azno_WơANV责X@ӭnDAM򪾹DznƬOOHIoӭnDyʥ]z|bztΤWQy]zF
2. y]zAMNOn}lӶǰeAǰeMOǥѺdӶǰeoAҥHƳoӮɭԷ|QedWF
3. ӦbdN]ʥ]ǰeXheA|ť@UboӶǰeɶIWAO_L PC PɦbǰeApGSܡAʥ]~iHeXhA_hNLkǰeAݭnAU@ť~ǰeI
4. nFA}lǰeANݭnǧU route tables WhAo route table NIOСAڭ̪ʥ]NOgL@hS@h`I(nodes)ӰeFتaI
5. FتaAAӫhO𫍧DNʥ]UӡAøgL@~tΪѶ}ʥ]AozҭnDơAMb̾ڭnDeӵ^Iӳoӵ^SݭnWoˤ@Ӭy{FIoӮɭԴN|ܦNƥ]->d->ǰe->....FzùeI
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MAouO²檺@Ӭy{ҤlA̭]tFܦhTAҦp(route)Bʥ](TCP packet)B}(IP)B@ɴC骺ws@¦NNݭnzѡ㧐Uڭ̥Ф@U OSI ChwAA@Ӥ@ӤӤЦUӼhһݭnDeI
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TCP/IP P OSI ChwG
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ھڤWƹB@y{觋Aڭ̴NDAQniǿANnwAӥBٻݭnL\઺B@A~sW Internet CMӱznAѪOAw}oӥiOu@aڡAåBAiHB@@~tΤ]Ou@ذڡIpGjaW۪ۤv[cAiN|y W P@~tλP L P@~tΤƵLkiǿ骺DաIN˸FIOڡIҥHAFWdҦw}oӶ}oXӪ~OiHeA]FP@~xiHݮe Internet ǿ觋A]jaҵoinwNonŦX TCP/IP oӨwڡI
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{쫬̦Obj 1970 ~NFeU Advanced Research Project Agency (ARPA) ҵoi ARPANET [cAӸӺ[cgLUjM|աBsHĥΡAåBNΩ Unix tΤWC]oӬ[c۷㦳ΩʡAרOL]pO}AëDMݩYӨpAҥHNVӶVhJ TCP/IP ϥΤC TCP/IP غا޳NAO Internet Network Information Center (INTERNIC) ҲΤ@zP@Aܩ TCP/IP зǫhDnH Request For Comment (RFC) ޳NiΦ}AziHb ftp://nic.merit.edu/internet/documents/rfc/ UҦ RFC I
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TCP/IP WO Transmission Control Protocol / Internet Protocol (TCP/IP)AiHⳡӻAY TCP P IP AIP u@ObhAoӴNOڭ̱``ݨ쪺| 0-255 QiƦråHpIy.zj}ƾڡAҦp 192.168.100.100 o˪զXANcF IP CnbںWNƥѳoqǿt@qANoݭn IP IP ǿFCܩ TCP h󬰽AW IP ǰet@ IP NOzL TCP wѻPFI TCP/IP ڭ̱Nb᭱`ԲӪC
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F TCP/IP oӰ¦w~AFҦnw}o̳P@ǡA]N OSI ( Reference Model for Open System Interconnetction ) ͤFC_ӡA OSI uO@ӼҦ (model) ALèSwʪWdnw@wnppAӬOX@ӫު̾ڦӤwIo OSI NӺB@ѳ̩hh̤Whμh@CjAҥHڭ̤@q٬ OSI ChwAOWw̩hh̤WhμhһݭnŦX̾ڡCpUҥܡG
Ϥ@BOSI Chw
@ åBAboChwASʤjsաA@ӥΦb¦(wwP})譱ADnWwFwP̩hwFt@ӫhOPϥΪ̤wAϥΪ̻Pn}o̥iHoǨwӳ]pۤvε{IjPWNpPUG
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• ¦GhBƳshBh
• ϥΪ̤譱GǿB|͡B{μh
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ڭ̥iH²檺ΤUӵyLAѤ@Uҿת OSI ChwOtdH
@ @BOSI ChwChtdu@

OSI ChwW	Ӽhtdu@
h	JMu@ڪB@̬OqlTHζǻqlTw]ơAҦCNnzѬqlTFIMoǵwtƴNݭniWdAnҦC鳣㦳zѹqBiBHΤPuW檺WdCҥHoӼhŴNWdF]AUӺC𫗪wqB٦sAAҦp ethernet d٦ RJ-45 uCMաApGzQnoiCw骺ܡAzwNݭnŦXoӼhŪWwաIMXӪwiNLkPLW~qoI
Ƴsh	ѩǰeƪCOHOqlTiǰeAҥHڭ̪ƭnϥγo˪TǰeɡANݭnqUغAإ](Frame)FA~TOƥiHbPCiǰeʧ@CҥHAbo@hNqF frame 榡HγqL觋C @ ƹWAC frame |㦳@ Media Access Control (MAC, @ 6 bytes }) }AoӦ}OӦ۩CA²檺ӻANOddաIC@idbXtɭԴNwg㦳@ӿWSӥB|ƪdANO MAC (@]|٬ Hardware Address, w})A frame nǰeӷPتaANO̾ڳo MAC ӶiǰeCܩǰeL{إ]򥢡Bsoeإ]Bʥ]T{A]OboӼhŷQwqoI @ boӼhŷAӭnwANO Address Resolution Protocol (ARP) Ao ARP wDnNOΨӹ MAC P IP nu@Iڭ̷|JӪC
h	ڭ̦bW쪺 TCP/IP wA IP NOhoӼhŪneFChDn\NOnʥ] (packet) iHbPiǻIЪ`NAڤWbiqlTǻOh MAC P frame AӳoӺh packet hOΨӳBzw}C @ bo packet QoeeAboeݪq|oӫʥ]إߪY(header)AHeader ̭T]tFӷPتݪ}A٦ƶǰekPy{AH@o packet bΪ̬Oli ( route )̾ڡCڭ̱``b]w IP H route table Oo@hWwC
ǰeh	Nڭ̭nHHɤ@ˡA`OoƩJHʦAʰ_ӧaCoӶǰehu@@NONqơy]zʥ](packet)AAHѺhhiYإߡIboӼhŷAPɷ|]w`IƶǻHο~˴MץkC @ ѩ󪫲zWAҥHb@ƪǻAq`uƤd byte ƶqCFTOצhjΪ̦hpƳiHTFتaA]ƴN|boӼhŷQ]ApGƤӤjAN|QƭӤpʥ]ӶǰeAåBPɧQΤ@˴qӨϸƥTFتaCӦpGƫʥ]}lA]i歫soeu@C
|ͼh	boӼhŷAwqFӦ}qDsP_A]NOqPqqҦC|ҨӻA Client `I A Server `I BAƭnb A P B iǰeɡAⳡq|i|͡AHT{O_iHiǰeʧ@C|ͪL{pUG `I A n B nDإ߳suɡAA |oXysuШDzTʥ]AӰTWa SYN ŸF `I B TApGTw A sunDAN|^@ӡyT{ШDzTʥ] A AӰTWha SYN/ACK ŸF M`I A Aצ^ B @ӡyT{suzTʥ]Aa ACK ŸAoӮɭԴNiJFƶǰeqFI `I A ƶǰeA A |oe@ӡyפsuzTʥ]Ahbo B ^yT{פzTANFӦsuI WYOWyTV洤, Three-Way Handshackzu@zաINObo@h̭FIҥHڭ̥iHAb|ͼh̭iHíwiasuDI
{h	ڭ̦bε{Wһs@XӪƮ榡@wŦXǿ骺зǽsX榡IҥHAboӼhŷADnʧ@NOGNӦۥaε{Ʈ榡ഫ(Ϊ̬OssX)зǮ榡AMA浃UǰehwӶiBzCMաApGOӦۻݪơAoӼhŤ]|NзǽsXഫε{һݪ榡AA浃ε{BzC]NOAoӼhŷwqFƾڪykHή榡Aε{ykP榡ŮɡA٥iHi½Ķ(ssX)u@C
μh	{hu@ONӦε{নǿ骺зǮ榡AܩμhhOPε{C

@
ѤWAڭ̤z OSI ChwAC@hO㦳ʪAåBhnƤA~kiW@hu@CҦpni IP ]wӻnFApGSAi IP ]wHӦpGSCFAiƶǰeHIt~AbC@hwAȻPӼh۹Cثeo̥²檺Aбz~ݧANjAѤFI
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bU@`̭Aڭ̱Nw OSI Chw̭C@hi满AHjaeAѾӺ[cI

b OSI ChwA̩hThQw쬰hAoThO̰򥻪[cFIMoThq`wgQXb@~tλPw̭FAҥHڭ̮ڥݭn߳oThwALApGDoǰ¦A󥼨ӦbilܮɡAUOܤjIUڭ̴NOӽͤ@ͳoThDneaILAb}leAڭ̱oӽͤ@;Ӻǿ쪺wq
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ǿ
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Q@QApGSqܡAڭ̪O_qLHIMI]NOqlTǰeڡIpGSqAMNSkǰeTFCӹqlTu 0 1 ڡAҥHb쪺pWA@q`OHGi쪺 bit 쪺Co bit Pڭ̳q`Ψӭpɮפjp bytes sʡHG
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1byte = 8bits
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ҥHաA@ӻAڭ̬ݨ쪺Ѫ (Internet Services Provide, ISP) ҫź٥L̪ ADSL ǿtץiHF U/W 512/64 Kbps ( Kbits per second) ɡA Kb iO bytes ӬO bits IҥH 512/64 Kbps bڪɮפjpǿtפWA̤jzתǿ鬰 64/8 KBps(KBytes per second)AҥH`Ut׬bC 45~50 KBytes oIP˪DzAbdΪ̬O@ǺC骺siWAL̳|ź٦ۤv~iH۰ʿѶǿt׬ 10/100 Mbps ( Mega-bits per second)AIӼƭ٬OoAH 8 ~Oڭ̤@`Ϊɮ׮eqp⪺ bytes Io˥iHAѶǿ쪺NqFܡHI
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h
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JMOѵwӶiTǻAҥHbo̧ڭ̴Nӽͤ@ͺC骺B@觋aILC骺s觋۷hAҦpӤ`yPγsuzHθu׬y (bus) AHΥHaxǪLuAPbTǻWOӤ@˪CLAѩ Bus suҦOezѪ@سsuҦAҥHUڭ̥H򥻪 Bus suҦӶi满CpUϥܩҥܡG ( M@ax̱`suҦPμҦAL򥻭zW٬OP Bus GuҦۦP )
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ϤGBH bus sqܷN @
ҦqgLP@ӺC(NOV@Dnlu)ӶisCoӺCWݭn`NaOH
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• CG

OyCzFA̰¦CNOyuzoA]ڭ̳OzLuӶiqlTy ( AбzdNAo̬OHuҡAMC٦۷h˦I)CnFAЪ`NOAҦqniƶǻɭԡANOݭnϥΨoөҿתCAӥѩҦqsboӺCWAziHNo Bus uO@ӡy@ɴCzoIåBAoӦ@ɴC骺ǿ魭y@ɶIWAu঳@ϥγoӦ@ɴCzAoӷ۷nAOUӧaI
@
{bڭ̪DTOǥѺCӶiǻAӳoӴCb@ɶIWȯ@ӾϥΡIGupܡAUDӦpѨMOH
@
1. Uq򪾹DӮɶIWSLbϥΩOH
2. pG PC1 P PC2 nۤqܡAL̪TO˶ǿ骺A]NOA PC1 򪾹DӰTOne PC2 OH
3. pGP@Ӯɶ̭ⳡqHWPɨϥγoӴCA|ͤ򱡪pH
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UNݭnwWDӻ@UG
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• ѩo@ɴCbCӮɶIWȯ@ϥ ( oӮɶiOXdXU@AܵuաI)A]ApG PC 1 oqQnQγoӴCoeƥXhɡALNnT{ɦboӴCWSLbϥΡCoӮɭ PC1 N|oe@ӰTʥ]oӴCWhAiDoӴCWҦqDyޡIڭnϥγoӴCFzIӨL PC2 ~ PC5 bo˪Tʥ]AN|Ȯɰyۤvu@A PC1 iHQϥκCǰe(oӰy]OܵuաIzPıXӪ ^_^ )CPC 1 oeTʥ]oӦ欰NOҿתyzsz(Physical Broadcast) FAӳoӰʧ@]O̩hʧ@oI
@
• DFzs ( Physical broadcast ) ʧ@AAӡApG PC1 P PC 3 PɳQnϥκCOHIoӮɭԡANnݬO֥ǰeXsHAMOmĹIҦpG PC1 PC3 @BV@ɴCeXzsHA PC3 N|yA쵥 PC1 NӦu@A~|oezsHFCxIzSo{oӦaܩ_ǰڡHIJM PC 1 wgmĹAU@ PC 1 nǰeưF 100 MB A PC 3 O쮻gFH I^ڭ̴쪺 OSI Chw̭yǰehzaA̭FGѩzY ( utաBҦPյz ) ACiǿɡAӦyʥ]jpzOIҥHApG PC 1 ƯuF 100 MB ɡAL]Lk@NN 100 MB ƥ]@ packet ACSkǿ騺jʥ]AҥHMNoN 100 MB}ƭӤp packet A@@ǰeXhաIӨC physical broadcast ȰwӦ packet oeӤwApGo packet oeAoA~i@ physical broadcast ~AoeU@ packet I]Ao 100MB ǰeon PC1 boӦ@ɴCWoeh physical broadcast ~IҥHաApWҤlӬݡA] PC1 nǿ 100MB PC3 nǿ 10MB ɡAL̬OiHPɶiǿ骺AuObC骺ϥΤWAN|_i檫zsAPC1 P PC3 ӷmӷmhA򪺱N@Ӥ@ packet oeXhIoӮɭԺCNܦաI
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• WҤlA PC1 P PC3 iiynzPɵoXzsTOHIMiաIb@ӫc@ɺCAѩiϥΪ̲hA[WϥΪ̥iॿbjqǰeɮ׸ơAoӮɭԴNeoͦPɵoezsHDFIoͦbP@ӺCWⳡDHWPɵoezsTɡAⳡDӦzsTN|LġAⳡDN|iƪǰeCL]ݭnӾ߳o˪pA]ⳡD|ݤ@qɶ~Ai檫zsʧ@IӦbݪɶWAOyb@qɶ̭H@ӮɶIzӦAi檫zsA(Ҧpbd@ɶAⳡDH@ӮɶIA@Din來d@At@Td@Ao˴N׹LAPɵoXzsTDC )ѩOH˪A]ӤӮeAyPɶi檫zs{HCU@uSPɪzsAS|ݤU@....̧ǤUhAnWL 16 HApGٯuܤ(]vuӧCF)APɶi檫zsANpաIzCNȱIL]OߡAs reset ( ӺLA} ) NnաI ^_^""
@
• ѤWpӬݡACWGbY@ӮɶIɥu|@ӫʥ]biǰeA򦳨Sioͤ@Ӻ@ɴCWPɵoeʥ]pOHMաI{bz] PC1 PC5 ZOܻ(] 50 m nF)A PC1 P PC5 oeXzsAjanǰeTɭԡAѩ PC1 P PC5 ZӻFA]^ɶAoӮɭԥiN|yD~PA{ɴCWS󪺾bǰeơAҥHNy PC1 P PC5 PɶǰeXƦbCWAoӮɭԴN|oͩҿתyʥ]I ( collision )zpFI]CW@ɶȯह\@ӾϥΪIҥHʥ]IN|yӫʥ]l{HOI·аաI]ʥ]lFAҥH PC1 P PC5 SoANӦ packet soe@ASonzs.....ӬFקKʥ]IDAҥHثeW|ϥΤ@غ٬ CSMA/CD ( Carrier Sense Multiple-Access / Collision Detect ) ޳NקK]ʥ]IyƷlDILAѩܪC餣PAҥH٬Oܦi|yIաI

@
W쪺XӻIAOww骺]pAzMݭnDwO]pAO̦n٬OݭnDWzoǭzAH~|DpGXFDAnphѨMI
@
bͧF@ɴC𫗪AAӽͤ@ͥثe̱`tơANOAӺd ( Ethernet ) Cثeڭ̦bqD᭱ݨ쪺qܽuYAOj@IAY㦳KuѡANOAӺdCoӺd̤jSOL㦳@ӾZbW} ( Y Notebook W PCMCIA dOiժ ) ANO Media Access Control (MAC) A]``Qڭ̺٬w} ( Hardware Address )Cڭ½^ OSI Chw̭ƳshAbӼhŤACӮإ] ( frame ) nǰeXhAnHw}ǿ骺ӷPؼСAoNOdPdƶǿ骺̩hTFCҦpPˤWϥܡA] PC 1 nNƶǰe PC 2 WhɡAƫʥ]Nno PC 2 Dd MAC A~Nƶǰe PC2 OIoӳNݭnbƳshӶi满FC
 @


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Ƴsh
@
b TCP/IP P OSI ChwӤp`Aڭ̪D@ɤWϥΨӿѹqDO IP Ao IP Ob OSI ĤThA]NOhFCӥѤWhСAڭ̤]iHDƫʥ]ѳoӥDU@ӥDAϥΪO MAC oӺdd ( Hardware address ) ӶiǰeA IP P MAC YڡHI|ӨҤlӻAP˪HWϤGҦnFA] PC 1 IP O 192.168.1.1 PC2 IP O 192.168.1.2 Aƭn PC 1 ǰe PC 2 ɫA쩳OiǰeH]աI]ƭnǰeNoDddA] PC1 nD PC2 Hardware Address A~Nƥ PC1 dǰe PC2 dWC]NOA IP nP MAC ( NO Hardware address ) _Ӥ~IoӮɭԡANݭnϥΨ Address Resolution Protocol (ARP) wFCUڭ̴NФ@U MAC 榡AH ARP eC
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• MACG

bثeڭ̨ϥΪAӺdWAbXtɫNwgZ@ӺddbWFA]oӥdOH۵w骺AҥH@ڭ̤]٬w} (Hardware address)AӥBC@idWd|ơIƹWALOQ٬ Media Access Control, MAC աIMAC 榡O 16 i (bytes) ƾڲզX_ӪAҥHL@ 6 bytes A򥻪榡G
aa:bb:cc:dd:ee:ff
MAC OAӺAƶǿ骺n̾ڳI~AMAC bӬ[]𪺮ɫAΨӺިYiSwdO_qLʥ]LoWhn]weIҥHAХ MAC @ӧ㪺AѧoCb Linux P Windows 2000 UAn򪾹Dڪd MAC OH

1. b Linux UG [root@test root]# ifconfig eth0      Link encap:Ethernet  HWaddr 00:05:D3:43:E4:80           inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 ..... @ 2. b Windows 2000 UG C:\> ipconfig /all Windows 2000 IP Configuration .....         Physical Address. . . . . . . . . : 00-05-D3-43-E4-80 .....

pPWҥܡAb Linux UADn榡OHy:zj}Ab Windows UAhOHy-zӹj}ILצpAϥOoLO16i쪺ƾڲզNOFIϥΪ[觋iHH ifconfig H ipconfig ӤUFOC
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• Address Resolution Protocol, ARPG

{̱`ΪǿOϥ TCP/IP Ӷi檺AҥHC@DMn@ IP ~IMӧڭ̪DƨOϥ MAC bPd۶ǻA]An]w@ IP P MAC k~AɴN ARP wͤFCARP oӨwbثeDn@~tθ̭sbۡAҦp Linux ḒN@ ARP table Ӭ IP P MAC TCҥHAeϤGA PC 1 (192.168.1.1) nNƶǰe PC2(192.168.1.2) A PC1 N|ѦҦۤvtΤ arp table A 192.168.1.2 MAC AANƶǰe쨺 MAC hI
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ARP table DnOO IP P MAC A ARP O򲣥ͪOHoNݭnQר޿s ( logical broadcast ) ʧ@FIЪ`NA޿sP Physical broadcast ( zs ) O@˪A Physical broadcast ODQnb@ɴCWǰeƮɡAΨӽT{CO_iHQΪ@Ӱʧ@A޿sʧ@@hOb IP P MAC A]NOyzsDnOwbP@Ӫzq@ɺC𫗪ʧ@A޿sDnOwhn}ӨӶi檺ʧ@zA˱N̷dVFCnFADOإ ARP table OHڭ̦P˥H PC 1 ( 192.168.1.1 ) nǰeƵ PC 2 (192.168.1.2 ) ҦnFG
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1. b PC1 iƶǿ骺ɭԡAѩ ARP table S ( ]sWI ) AҥH PC 1 D 192.168.1.2 o IP O MAC AM]NLkǻƤFCoӮɭ PC 1 N|yP@쪺qi޿s( logical broadcast )zA PC 1 |oe@ӱa MAC Pؼ IP (boӨҤlA]NO 192.168.1.2 ) ޿sʥ]줺q( bϤGҤlA]A PC 2 ~ PC 5 |o޿sʥ] ) F

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2. b PC 2 ~ PC 5 o޿sʥ]Aѩo޿sʥ]nD^O 192.168.1.2 A] PC 3 ~ PC 5 äOo IP ҦHA]N|No޿sʥ]󤣲zC PC 2 o޿sʥ]ɵo{ӫʥ]nD IP OۤvAɥLN|oe@Ӧ^ʥ] ( Ӧ^ʥ]̭Nt PC2 ۤv MAC ) PC 1  F

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3. PC 1 boӦ^ʥ]ANDF PC2 o 192.168.1.2 IP MAC FA PC 1 oD ARP table N|DʪN IP P MAC LgJ椤աIӬJMwgDF IP MAC FA] PC1 NiH}lNƶǰe PC 2 FI

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4. ӡA PC 1 nNƦAǵ PC 2 ɡAL|Ѧۤv ARP table ̭hMO_ӥD IP MAC TApGF PC 2 (192.168.1.2) MAC A PC 1 N|oe޿sʥ]AӬO̾ ARP table ̭TӱNƪǰe PC 2 dOI]NOG
• pG ARP table ܡAƴN|ǰeӥتahAӤ|iy޿szF
• pG ARP table SܡADNS|P@줺qiy޿szC
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~AЯSO`NAARP table OʺATAL|HH۱z̭q IP ʦܤơAҥHAYϱz``ʱzq IPAnߡA] ARP table |۰ʪs IP P MAC 椺eI( ҥHCs}A ARP table eNhoI )ګdXӥثeڪ Linux Ḓ ARP table OHIiHϥ arp oӫOI

[root@test root]# arp [-and] hostname [root@test root]# arp -s hostname(IP) Hardware_address ѼƻG -a GܥXثeDҦ IP MAC A -n GNDW٥H IP A -d GN hostname hardware_address ARP table R -s G]wY IP hostname MAC ARP table dҡG [root@test root]# arp Address          HWtype  HWaddress           Flags Mask         Iface localhost        ether   08:00:20:C5:89:4D   C                  eth0 [root@test root]# arp -n Address          HWtype  HWaddress           Flags Mask         Iface 192.168.1.1      ether   08:00:20:C5:89:4D   C                  eth0 [root@test root]# arp -s 192.168.1.100   01:00:2D:23:A1:0E

@ӻAϥ arp oӫONiHdz Linux DW arp FI Linux OaIMA Windows 2000 ̭]Pɦsb@ arp OAiHլݬݳI
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bͧF OSI Chw̭hPƳshAUӴNO̭nhFILA]h̭ IP bӭnFAҥHڭ̱NLWߥX@Ӥp`~򤶲СCMAUNWߪӤлP IP @ǷA]tF Netmask, Broadcast, Gateway Hκ쪺C

{ѤF̩h@ɴCPƳsh ARP MAC AUӭnjaЪNOӥiRSi몺PyInternet Protocol, IPzFAIP OҦ¦ASFLAzNuO@oKڡIӻ{Ѥ@UaI
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IP զG
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ڭ̥ثebWϥΪ IP wOĥ|A]NOQ٬ IPv4 @ӨwCboӨwA̭nNO IP զFCIP DnO 32 bits ƩҲզ@ռƾA]NO 32 0 1 ҲզƾڸơA]us@AҥH IP զMNOq{ѪGi쪺ܤ觋FCLA]HGibOxAҥHFH̹Qi쪺̿ʡA]ANN 32 bits IP |pqACqt 8 bits AN 8 bits p⦨QiAåBC@qHpIj}ANFثejaҼx IP ѼgҼˤFCpUҥܡG
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IP ܦG 00000000.00000000.00000000.00000000 ==>0.0.0.0 11111111.11111111.11111111.11111111 ==>255.255.255.255

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ҥH IP ̤piH 0.0.0.0 @ 255.255.255.255 IƹWA IP զAFH 32 bits զ觋ӻ~A٨㦳ҿתyzsbCUNӽͤ@ͤOaI
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쪺
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ƹW IP 32 bits ƤAiH HOST_ID P Net_ID ⳡAڭ̥H 192.168.0.0 ~ 192.168.0.255 o C Class @ҤlӻnFG
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192.168.0.0~192.168.0.255 o C Class G 11000000.10101000.00000000.00000000 11000000.10101000.00000000.11111111 |----------Net_ID---------|-host--|

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b C Class dҷAeTռƦr (192.168.0) ٬ Net_IDA̫᭱@ռƦrh٬ Host_IDCP@ӺwqOybP@ӪzqAD IP 㦳ۦP Net_ID AåB㦳WS Host_IDzAo IP sNOP@Ӻ줺 IP qաI ( G򪫲zqOH|ҨӻAWϤGҦDOϥΦP@ӺCb@_AoӮɭԳoǥDb˸mWOsub@_ANiH٬oǥDbP@ӪzqFIPɨýЪ`NAP@ӪzqAiH̾ڤP IP ]wAӳ]whӡyIP qzI  ) ҦpWҤl 192.168.0.1, 192.168.0.2, ...., 192.168.0.255 o IP NOP@Ӻ줺 IP s(P@Ӻ]٬P@ӺqI)AЪ`NAP@ Net_ID A㦳ۦP Host_ID AҦpWϤGA PC 1 P PC 5 Pɨ㦳 192.168.0.1 o IP A_hN|o IP ĬAi|yⳡDSkϥκDIP@Ӻӫ]wAPN IP ]wbP@Ӻ줧nBOH
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• bP@ӺqANet_ID OܪA Host_ID hOiơA~A Host_ID bGi쪺ܪkAiPɬ 0 ]iPɬ 1 AҦpWҤlA 192.168.0.0 ( Host_ID 0 )H 192.168.0.255 ( Host_ID 1 ) iΨӧ@qD IP ]wA]NOAoӺqiΨӳ]wD IP O 192.168.0.1 192.168.0.254F
• bP@Ӻ줧AC@DiHǥ޿s ( logical broadcast ) o줺LD MAC IPF
• ѤW޿sʧ@o MAC (Y ARP w)AbP@Ӻ줧ADƥiHzL NIC ( Network Interface Card, d ) iǰeF
• bP@ӪzqApGⳡD]wP IP qAhⳡDLkH޿siƪǻ ( bS]wS route WhpU )C
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ҥHAڭ̮a̪ҦqM]wbP@Ӻ줺O̤KA]p@ӨC@qiHiƪyAӤg Router ( Ѿ ) Ӷiʥ]qOI( Router ob~|ΡI )CnFAڭ̤WO C Class A򦳨SL Class OHӥBL̤SOϤOHثe Internet N IP ²檺TӺqAO]wҿת A, B, C T Class AL̪hpUG
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HGi컡 Network Ĥ@ӼƦrwqG A Class : 0xxxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx@==>}YO 0  @@@@@|--net--|---------host------------| B Class : 10xxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx@==>}YO 10 @@@@@|------net-------|------host------| C Class : 110xxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx@==>}YO 110 @@@@@|-----------net-----------|-host--| @ HQi컡 Network wqG A Class :   0.xx.xx.xx ~ 126.xx.xx.xx B Class : 128.xx.xx.xx ~ 191.xx.xx.xx C Class : 192.xx.xx.xx ~ 223.xx.xx.xx

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bWAiz|ıoܩ_ǡAxI 127.xx.xx.xx 򤣨FHILӤ]O A Class @qaHISAOFA]oӺqQh@~tΰj ( loopback ) ΤFIbUӧ@~tηA޸ӥDw驰SdAF@~T{ۤvSDAҥHN 127.xx.xx.xx o A Class q@~tηAӰ^աIҥHաAo 127.0.0.1 NiHΨӰ쪺]wFC
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Netmask γ~ (į) Pl
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bW@p`쪺 A, B, C TӼhŪO IP ww]tAbo˪hŷAڭ̥iHo{ A Class iHΩ]wqD IP ƶq ( Host ) uOܦhAbP@ A Class 줺ADƶqiHFy 256 X 256 X 256 - 2(HostID01) = 16777214zALAo˪]wp@įoOӦnIOHڭ̦^ OSI Chw̭@ɴCWAٰOo@ɴCWD A noeƥXhɫAݭniyzszӽT{CWSHbϥΧaHӨLDbo˪zsʥ]ANonNu@yUӵD A Nʧ@ALD~iU@zsCҥHpGڭ̬OH A Class [cӬ[]ڭ̪ܡA@DnǰeƮɡALҦDonyoIӥBApj줺A֩weoʥ]I ( Collision ) DAӥBbi޿sɫA^qDƶq]bOӦhFIp@ӡAӺįN|ܪV|IҥHA@ӻAڭ̳̦hȳ]w C Class Ӱϰ[cANs C Class ]ӤjFILAunOo@Ӻ줺nWL 30 HWDƶqA˺įN|n@I
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AF C Class ~Aڭ٬OiH~NӪIWӳ`ڭ̴ IP Net_ID P Host_IDA𫟺 C Class Net_ID F 24 bits AӨڭ٥iHNo˪ӡANOĤ@ Host_ID Qӧ@ Net_ID AҥHA Net_ID N 25 bits Aܩ Host_ID h֬ 7 bits Cbo˪pUAӪ@ C Class NiHQӤlAӨCӤlNy 256/2 - 2 = 126 zӥiΪ IP FIoˤ@ӡAboӺDbi޿sɡA^DƶqN֤F@bAMįhh֤֦InBաI
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nFADFljPpA{bnͪOA쩳OѼƨӹFlOHINO Netmask ( lBn ) γ~աIo Netmask OΨөwqX쪺̭n@ӰѼƤFILL]zѤF @_@CFUjaeOЦ Netmask ]w̾ڡAUڭ̤Ф@ӤeOЪkCP˥H 192.168.0.0~192.168.0.255 oӺ쬰dҦnFApUҥܡAo IP qiH Net_ID P Host_IDAJM Net_ID OiܪAN]LҦڪ bits wgQΥF ( 1 )A Host_ID OiܪANNLQOOd ( 0 )AҥHA Netmask ܴNG
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192.168.0.0~192.168.0.255 o C Class G 11000000.10101000.00000000.00000000 11000000.10101000.00000000.11111111 |----------Net_ID---------|-host--| 11111111.11111111.11111111.00000000  <== Netmask Gi   255   .  255   .  255   .   0      <== Netmask Qi

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NLনQi쪺ܡANy255.255.255.0zաIo˰O²hFaIӳo˪OФkA A, B, C Class Netmask ܴNoˡG
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Netmask ܤ觋G A Class : 11111111.00000000.00000000.00000000 ==> 255.  0.  0.  0 B Class : 11111111.11111111.00000000.00000000 ==> 255.255.  0.  0 C Class : 11111111.11111111.11111111.00000000 ==> 255.255.255.  0

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ҥHA 192.168.0.0~192.168.0.255 o C Class 줤AL Netmask NO 255.255.255.0 FIAӡAڭ̭责F Host_ID 0 HΥ 1 ɫ IP OiHϥΪA] Host_ID 0 ɫA IP OӺq Network Aܩ 1 ɫNܸӺq̫@ IP A]٬ Broadcast AҥHAb 192.168.0.0 ~ 192.168.0.255 o IP q̭ѼƴNG
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Netmask:   255.255.255.0   <==wqA̭nѼ Network:   192.168.0.0     <==Ĥ@ IP Broadcast: 192.168.0.255   <==̫@ IP iΪ IP ơG 192.168.0.1 ~ 192.168.0.254

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@ӻApGڭ̪DF Network H Netmask ANiHwqXӺ쪺Ҧ IP FI] Netmask NiHX Broadcast IP ڡI]Aڭ̱``|H Network H Netmask Ӫܤ@ӺAҦpo˪gkG
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Network/Netmask 192.168.0.0/255.255.255.0 192.168.0.0/24

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t~AJM Netmask ̭ Net_ID O 1 A C Class @ 24 bits Net_ID AҥHաANW 192.168.0.0/24 o˪gkoIoNO@쪺ܤkCnFA责 C Class ٥iH~il ( Subnet ) ڡAH 192.168.0.0/24 oӱpҡALnpAӤӤlOHڭ̤wgD Host_ID iHӷ@ Net_IDA Net_ID ϥΤF 25 bits ɡAN|pUҥܡG
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쥻 C ClassG 11000000.10101000.00000000.00000000 11000000.10101000.00000000.11111111 |----------Net_ID---------|-host--| @ Ӥl l@G 11000000.10101000.00000000.00000000  <==Network 11000000.10101000.00000000.01111111  <==Broadcast |----------Net_ID----------|-host-| 11111111.11111111.11111111.10000000 <==Netmask Gi   255   .  255   .  255   .  128  <==Netmask Qi Ҧ IP PܦG 192.168.0.0 ~ 192.168.0.127 192.168.0.0/25 192.168.0.0/255.255.255.128 @ lGG 11000000.10101000.00000000.10000000  <==Network 11000000.10101000.00000000.11111111  <==Broadcast |----------Net_ID----------|-host-| 11111111.11111111.11111111.10000000  <==Netmask Gi   255   .  255   .  255   .  128  <==Netmask Qi Ҧ IP PܦG 192.168.0.128 ~ 192.168.0.255 192.168.0.128/25 192.168.0.128/255.255.255.128

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ҥHAAӤUhɡAN|oӤlAӨӤl٥iHAӤUh (Net_ID α 26 bits ....)CIpGzuz IP, Network, Broadcast, Netmask ܡA߱zAӪADzߤwgZF@bաI ^_^
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IP P IP o觋
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Uӭnjaͤ@ͤ]OܮeyjaxZ@ӳANO IP IܦhBͱ``ť줰yuIP, IP, IP, IP....zгЦFꤣnӺiաIڤWAb IPv4 ̭Nu IP A@غ٬ Public IP A½Ķ@Ϊ̬O} IPAt@ثhO Private IPA½Ķyp IPzΪ̬OyOd IPzCo IP nOH²AunyӤzLLNP Internet WDi淾qANO public IPFLkP Internet WqANO Private IPzCoO@ӫ²檺kաI
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b IPv4 WɭԴN IP |pAӥBFIYǨp]wAONFp IP ( Private IP ) ͤFCp IP ]Ob A, B, C T Class UOd@q@p IP qANOG
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• A ClassG10.0.0.0    - 10.255.255.255
• B ClassG172.16.0.0  - 172.31.255.255
• C ClassG192.168.0.0 - 192.168.255.255
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ѩoT Class IP OwdϥΪAҥHäઽ@ Internet WsAMܡABۦP IP oIIZVáHҥHoAoT IP qNup쪺 IP qΡA]NOALUXӭG
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• p}ѸT~ ]NO^F
• ϥΨp}@ӷΥتa}ʥ]AzL Internet e ]IMoIM|Vá^F
• p}ѦҬ(pDNS)Au୭_ϥΡ]@˪zաI^
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oӨp IP nBOHIѩLpѤ~ѸTAҥHOAzN|Q Internet W Cracker ҧIOAMoAz]NLkHp IP ӡyWzoIҥH۷AX@ǩ|㦳 Public IP ~ΨӳW]wΡI_hzHKw@ǥiO Public IP qӳWz~]wɡAU@@ѯusW Internet FAҤOi|y Internet W Public IP ۦPFܡHIoiOx۪AnNzW IP qӭsվLOII֦FIU@zSnNoǨp IP eW Internet OHIo²A]w@²檺[W NAT ( Network Address Transfer ) D]wAzNiHzL IP (nAoӦb᭱]|I)Өzp IP q]iHsW Internet o(MOuAOܹyWzOI)
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nFA򰣤Foӹwd IP qD~A٦SLǪFOHIMOաIMڷFɶӰ XX OIHSA٦@ө_Ǫ A Class ANO lo oө_Ǫ ( `NGOpg o ӤOsI )o lo OQΨӧ@է@~tΤjҥΪ@ӺI²檺ApGzSw˺dbzWAOzSƱiHդ@UbzW]wƨ쩳iiHQAoӮɭԫAKKINOQγoөҿתjաIoӺqb 127.0.0.0/8 o A Class AӥBw]D ( localhost ) IP O 127.0.0.1 IҥHoAzҰʤFz WWW AAMbzD X-Window W https://# NiHݨzDoIӥBݭnw˺dOIիܤKaI~AzϥΪ mail BelOHҦpzDtΦp mail root oӤHOHKKI]NOϥγo@ӤjաInz TCP/IP ʥ]PAO_`ɡAiHϥγoI( ҥH@ѦHzGKIzDWSdAziHz WWW A]wO_TܡHoӮɭԥio^GMiHoIϥ 127.0.0.1 o Address rI ^_^... )
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zѤF IP Aڭ̤wgDFnsW Internet Nono Public IP ~iHAܩ private IP hOΦbpΪIӦpo Public IP OHثebxWaϦXӥio Public IP kG
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• Twʳ]wGڭ̥iHoTw Public IP Ao޹DiHOdzNBΪ̬OV ISP UTw Public IPCLAbϥΩTw Public IP ɡAznʪbz@~tγ]wnѼơF
• BʦGFWzk~ADzΪHƾھAHΥثeܬy檺 ADSL AOt@Өo Public IP kAuLѩoؼkAo IP O ISP HѪA]C ISP o IP iೣOTwAҥH]Hٳoبo IP 觋BʦF
• lu, Cable modemGQγVΪ̬OV Cable ]iHV ISP Uo Public IPF
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аOoAIP Nu Public P Private IP oءAӥѩo IP kPAiSHwźٯBʦBTwBʺA IP Aoܮey𫎆IJB̪ͭxZIҥHo̶ȧiDjaOoyPublic P Private IPzӤwIzunOoLNFILAH۵MN|zѪաI ^_^

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O ( Route )
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beƶǰeҦгObyP@Ӻz̭pAڭ̳OHϤGרҨӻCU@ڭ̪ƻݭnɡAƬOǰeOHoӮɭԴNݭnQר ( route ) FCҦpUϨҩҥܡANetwork A P Network B O}ӺAӥL̬Oǥ Server A DӶiw骺sC Network A PC 01 n Network B PC 11 iƪǿɡALݭn˪ǿ觋OH
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ϤTB²ѥܷN @
ѤWϥܤAڭ̥iHD Network A 192.168.0.0/24 oӺA Network B 192.168.1.0/24 oӺAoӺOઽ۳qIҥH PC 01 iHzL޿sH ARP table ӻP PC 02 ǿơAL PC 01 oLkP PC 11 ۤqA]oⳡDbP̭ڡINLkH broadcast 觋ӹFǰeTʥ]FC
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ƹWAⳡDणiƪǿAF MAC B ARP H IP ѼƬO_T~Aٻݭnܭn@ӰѼơANO ( route )Iثe@~tγܿˤAwgNP@Ӻqإߪ򥻪ѤFAҥHڭ̦bP@ӺqɡANLҼ{ѡAӥiHǥ ARP AӪHd (NIC) iƪǿCOAU@oͤFW[c PC 01 P PC 11 pɡA PC 01 NݭnǥѤ@Ѿ (Router) LFƪǰeFI
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• Gateway / Router G/Ѿ\NObtdP줧ʥ]໼ ( IP Forwarder )AѩѾ㦳 IP Forwarder \AåB㦳޲zѪOAҥHiHNӦۤP줧ʥ]i໼\C
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H PC 01 nNƶǰe PC 11 רҨӻG
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1. PC 01 ƳQ]Aʥ]ƤWNܤ֨㦳ӷaPتa IP }F
2. A PC 01 |Rӫʥ]تa IP }O_bP@ӺApGӫʥ]ObP@ӺAh PC 01 iHǥѥL ARP H޿sӨoتa IP MAC Aöi@BӶiӫʥ]ǰeF
3. LboӨҤlA] PC 11 äb PC 01 Ҧb줧A PC 01 |ۤvѪ ( Route table )Aݬ PC 11 bbۤvѪYӳWhAYAh̷ӸӳWhǰeU@ӥDh(q`NO Router աI)F
4. bڭ̳oӨҤlAèS PC 01 SѳWhAҥH PC 01 O䤣 PC 11 Ҧb쪺ѳWhA PC 01 N|ӫʥ]ƪᵹb PC01 ѳWhyw]Ѿ, default gatewayzDA]NO 192.168.0.254 Gateway (GW) WhAѩ Server A 192.168.0.254 P PC 01 ObP@Ӻ줧AҥH PC 01 OiHP Server A ǰeƪ (G]NOA Gateway PzDAnbP@Ӻq~I)F
5. Server A 192.168.0.254 ӫʥ]A|̷ Server A ۤvѪ 192.168.1.1 oDѳWhInbۤvt@Ӥ 192.168.1.254 P@ӺqAҥHzL IP Forwarder \ANӫʥ] 192.168.1.254 ǰe 192.168.1.1 PC 11 WhI
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jPpNOoˡAҥHաAC@Ḓ|sbۤ@ӸѪ ( Route table )AƪǻN̾ڳoӸѪiǰeIӤ@ʥ]wggѸѪWhǰeXhADNwgAޫʥ]yVFA]ӫʥ]yVNOU@ӥD (]NO Router )ӶiǰeA Router bǰeɡA]O̾ Router ۤvѪӧP_ӫʥ]Ӹgѭ̶ǰeXhIҦpUϨҡG
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ϥ|BѪ @
PC 01 nNưe Server Bingo hAh̾ڦۤvѪANӫʥ]e Server A hAServer A A~e Server B AMb@Ӥ@ӪOLeUhA̫`OiHF Server Bingo C
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MAWרҬO@ӫ²檺ѷAƹWA Internet WѨwPܤƬO۷A] Internet WѨäORAALiHHɦ]ҪܤƦӭ׭qCӫʥ]ǰeVC|ҨӻAƦ~ebs˦]gIuɭPxW赓Ӻlu_CLn_M٬OqAOH]ѤwgP_X赓luפA]L۰ʪɦVxWFὬuAMp@¶F@jAӥByj먮ALʥ]٬OqNOFIoӨҤlȬOQiDjaAڭ̤WѶȬO@ӫ²檺RAѱpApGQn`JA route AЦۦѦҬyI ^_^ C
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[D
@
JMѬOo򪺭nAӥByѤ@]w~AN|yYǫʥ]LkTeXhIzҥHڭ̷Mݭnnn[@Uڭ̥DѪաI٬OЦA`N@UAC@DۤvѪI[ѪO²ANO route AoӫOAڭ̦b᭱`A~򪺤СAo̶Ȼ@Ǥ²檺ΪkG
@

[root@test root]# route [-n] ѼƻG -n :NDW٥H IP 觋 dҡG [root@test root]# route Kernel IP routing table Destination     Gateway         Genmask         Flags Metric Ref  Use Iface 192.168.0.0     *               255.255.255.0   U     0      0      0 eth0 127.0.0.0       *               255.0.0.0       U     0      0      0 lo default         192.168.0.254   0.0.0.0         UG    0      0      0 eth0 @ [root@test root]# route -n Kernel IP routing table Destination     Gateway         Genmask         Flags Metric Ref  Use Iface 192.168.0.0     0.0.0.0         255.255.255.0   U     0      0      0 eth0 127.0.0.0       0.0.0.0         255.0.0.0       U     0      0      0 lo 0.0.0.0         192.168.0.254   0.0.0.0         UG    0      0      0 eth0

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bWҤlAڭ̥H PC 01 AӶi满Cѩ PC 01 192.168.0.0/24 oӺAҥHDwgإߤFoӺ쪺ѤFANOy 192.168.0.0 * 255.255.255.0 ... z@ܪTIzUF route ɡAùWFoW@TӸѳWhAĤ@欰yتazAҦp 192.168.0.0 NO@Ӻ쫣A̫@ܪOynhoӥتanϥέ@ӺIzҦp eth0 NOd˸mNաCpGڭ̭nǰeʥ]bѳWh̭ 192.168.0.0/255.255.255.0 Ϊ 127.0.0.0/255.0.0.0 ̭ɡA]ĤG Gateway * AҥHN|H᭱ӶǰeXhAӤzL Gateway I
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U@ڭ̭nǰeʥ]تa IP bѳWh̭AN|Nʥ]ǰeydefaultzҦbӸѳWhhA]NO 192.168.0.254 Gateway IҥHAXGC@D|@ default gateway ḼtdҦD줺ʥ]໼IoOܭnI^_^Ihѥ\P]wkAڭ̦b᭱y² Router []z|AΩOI
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@պ]wݭnѼ
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ѤWФAڭ̪D@DnϥκAn IP A IP ]wANn IP, Network, Broadcast, Netmask ѼơA~AٻݭnҼ{Ѹ̭ Default Gateway ~TNDP쪺ʥ]LǰeXhAҥHA@զXz]wݭnǸƩOHINOG
@
1. IPF
2. networkF
3. netmaskF
4. broadcastF
5. gateway
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SINOoǸơIpGzOϥ ADSL ӤWܡAWoǸƳO ISP zAzunϥμ{i漷 ISP u@AoǸƴN۰ʪbzDW]wFIOpGOTw ( pdzN ) ܡANoۦϥΤWѼƨӳ]wzDoIʤ@iOIH 192.168.0.0 o C Class ҪܡAzNnbzDW]wnUѼơG
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1. IPG 192.168.0.1~254
2. NetworkG192.168.0.0
3. NetmaskG255.255.255.0
4. BroadcastG192.168.0.255
5. Gateway GCӤH]wPAи߰ݱz޲zIINOzۤvաI

ש󵹥LӨFʥ]榡aFIWNNjhOb̩h¦ѡAoۦnnzѲzѡIĤ@ݤSYAhݴXAåBڰtX갵ANeiJpFI]zwgDF̩h IP HάѼƪNqAӪDOAhwuOѸѪP_AHTwʥ]ǰe|AOoǨwèS޲ziѩC骺laDAΪ̬OtLHΨLiwpAӳyʥ]lΪ̳Q󪺪ACFϫʥ]ǰeL{㦳íwʻPiaʡAڭ̴NoѤ@MƥiHS~FتaC
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b TCP/IP oӨwզXATCP ( Transmission Control Protocol ) NOΨӰǰe@ӨwAMաA٦@ UDP wOIb TCP oӨwALѤFíwӥBiasuAAܩ UDP hO@ӤSoiasuAFCUڭ̴Nӽͤ@ͧaI
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qTfP Socket pair
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b}l TCP ʥ]eAڭ̥AѤ@DZ`TaI쪺OqTf ( Port ) oӪNCqTfͳOӦ۩@~tΪYǵ{ ( z]iHQO{, process ) 浲GC|ҨӻAڭ̷QnsW_oӺs WWW TɡAڭ̪s (Netscap ٬O IE nաI ) Nݭnbڭ̪qWH}Ҥ@Ӥj 1024 HWqTfӶiӦsuAMաAb_ꪺ WWW DWA]nҰ WWW AȡAM Client ݳsiӡHҥHALN|Ұ WWW AnAӳo WWW AnN|b_ꪺDW}Ҥ@Ӱfӵ Client ݪsAoӰfɴN٬bť ( LISTEN ) FIӷӰfsWåBTإ߰_suAƴNiH}lboӰfiǰeFI
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γ\z|ıoܩ_ǡAW쪺b Client ݪfݭnH@Ӥj 1024 HWfӶiosuOHoO]p 1023 HfjhwgwdSA ( Services ) ӶiӪAȪҰʤFAҦpW쪺 WWW AAw]ťfNO 80 oӰ𸹡Cثe۷h` ( Well Known ) fNOOdtίSwAnΪAӳoǰ𸹻PAȪWٹb Linux tηAOgb /etc/services ̭AUCX@DZ` Services P𸹪G
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• 21-20:FTP ( ftp-data )
• 22   :SSH
• 23   :Telnet
• 25   :SMTP ( e-mail )
• 80   :WWW
• 110  :POP3 ( e-mail )
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t~@Iȱo`NOAp 1023 HUfnҰʮɡAҰʪ̪nO root ~IoӭnAjanѰOFI
@

g@ӪBͰݹLڻGy@DWohAȡAڭ̸oDisuɡAӥD򪾹Dڭ̭nƬO WWW ٬O FTP ڡHIzIoNO port PGաI]C Client nL̩һݭnƳۦPAҦpW쪺 Netscape H IE L̩һݭnƬO WWW AҥHӳnw]N|VD 80 port DơFӦpGzOϥ cuteftp ӶiPD FTP ƯDɡA cuteftp o Client nMw]NOVD FTP f ( w]NO port 21 ) isʧ@աIҥHMNiHTL~o Client ݩһݭnƤFC @ |ӨҤlӻA@DNnO@h\ȦAӻȦ椺CӭtdP~ȪfNnOqTfAӧڭ̥NnO Client ݨӪʥ]CziJȦQnúǫHΥdbɡA@fAȤHN|ܱzӵfhúǡAMApGzOnAAȤHN|бzfhgơAzO|]aI ^_^CU@]FHIMӵfN|iDzyڤtdoӷ~ȡAzЦ^hIzAIҥHӦsuN|yLk\zI

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͹LFqTfAAӲ@Cӫʥ]򥻤eǸƩOHoNonͽר Socket Pair ( 諸Ӥf )FIoeXʥ]ɡADOھ IP ӧPOӷPتaiuAåBA]ݭn port number ӧi Client P Server OH@ӰfӶisuaIҥHOA@ӳsuʥ]Nܤַ|]tU|ӸTG
@
• ӷ IP ( Source Address )
• ت IP ( Destination Address )
• ӷf ( Source Port )
• تf ( Destination Port )
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o|ӫʥ]򥻸TO۷nIzonAѳI
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ʥ]ǰe
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DFXӭnfPTAAѤ@UOʥ]OHʥ]WǸTOHʥ]Nܹڭ̦blHH󪺮ɭԨӶl󪺼ҼˤFIH`OoJHʧaHӫHʤW`OogWoHH}AHH}PmWڡIҥHA@ʶlDn|ӳAOOGyHʪTBPHʤH󤺮eIzCP˪ATʥ]Dn]OӳA@ӬOY ( Header ) At@ӫhOe ( messages ) աIӤ@ӫʥ]nǰe̥hAOǥ Header TӶiRӶǰeաI Header ǭnTOHDnNpPW쪺Aܤַ|ӷPؼ IP BӷPؼ PortI
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nFA]ںPzD]wSDFA]ѨMFѪDFAаݯuʥ]ObⳡDiǰeOHƹWAʥ]ǰeO۷AӥBʥ]AP (TCP/UDP) ]|@˪ǰeCo̧ڭ̶|@ӡy۹iaʥ]ǰe觋zӤСCpUϩҥܡG
@
ϤBiaʥ]ǰeA
@ oeʥ]̵oeX@ӫʥ]̫A̦byTzoӫʥ]A|^Ф@Ӧ^ʥ] ( Acknowledgment ) oe̡AiDL̤wgFIoeݦoӦ^ʥ]A~|~oeU@ӫʥ]XhA_hN|N𫍧ʥ]soe@Ioثʥ]ǻ觋]Ҽ{𫎆쪺ʥ]AAҥHOia@ؤ觋CثeںW`ʥ]O TCP P UDP A𫟺 TCP su觋A|Ҽ{hѼơALO@سsuҦ(Connection Oriented)iaǿAܩ UDP hٲFϤӦ^ʥ]BJAҥHO@ثDsuɦVDiaǿCb@ TCP ʥ]ǰeL{A]ܤֻݭnǰeP^ʥ]ӽTwǰeXhƨSDAҥHLO۷ia@ضǿ觋ALNOǿP^ɶi|[@ICܩ UDP ʥ]N]֤FӽT{ʧ@AҥHMLOia@IAOtפWN TCP ʥ]nӪ֤FIUڭ̱N~򤶲 TCP, UDP H ICMP ʥ]TeI
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TCP, TV洤,
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nFAAѤFsuBJA]D TCP P UDP ʥ]إ߬OtsbIboӤp`Aڭ̥N TCP ʥ] Header e@²檺ЧaI TCP ʥ] Header eDnpUG
@ GBTCP ʥ] Header T

Source Port(16)					Destination Port(16)
Sequence Number(32)
Acknowledgment Number(32)
Data Offset(4)	Reserved(6)	U G R	A C K	P S H	R S T	S Y N	F I N	Window(16)
Checksum(16)					Urgent Pointer(16)
Options
Data ...... Message

@
WT۷nAyLAѤ@UUӸơG
@
• Source Port & Destination Port ( ӷf & ؼаf )GӷPؼЪfAoӮeAѧaIW~责Lf[OIALjդ@UA Linux daemon Wٹ Port number OOb /etc/services ̭IӥBAp 1024 HU Port u root ~ҥΡAܩ@ Client o_suAq`OϥΤj 1024 HWfI

@
• Sequence Number ( ʥ]Ǹ )Gbe OSI Chw̭LAѩغتAҥH@ǰeʥ]jpjȦƤd bytes AOڭ̪ƥijoӫʥ]ҥiH\̤jeqAҥHNonNڭ̪ƵLƭӫʥ]ӶiǰeتaDʧ@FCD򪾹Doǫʥ]OsʪOHNoǥѳo Sequence Number ӻUFCoeݭnoeʥ]ɡA|oӫʥ]]w@ӧǸAMA̾ڭnǰeƪסA̧ǪW[ǸC]NOAڭ̥iHϥλWȨӴU@ӫʥ]LǸ]wI

@
• Acknowledgment Number ( ^Ǹ ) GѭϤʥ]ǿL{Aڭ̪DbݱFʥ]A|^oeݤ@Ӧ^ʥ]AӦ^TNObo̰աIݦ TCP ʥ]åBqLT{ӫʥ]AN|̷ӭ TCP ʥ]oeǸA[WƪץHͤ@Ӧ^ǸAӪb^oeݪ^ʥ]WAo˵oeݴNiHDݤwgT\ TCP ʥ]FIҥHA Sequence P Acknowledgment number O TCP ʥ]ҥHiaOҰڡI]LiHΨ˴ʥ]O_TQ̩ұOI

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• Data Offset (Ƹv)GoOΨӰOYץΪ@C

@
• Reserved (Od)GϥΪOdC

@
• Control Flag (лxX)GлxXb TCP ʥ]suL{AO۷n@ӼлxAӻ@oӱXAMAӰQקaG
• Urgent data GpG URG 1 ɡAܳoO@Ӻ檺ʥ]ơAuBzF
• Acknowledge field significant GWO쨺 Acknowledgment ܡH ACK o Flag 1 ɡAܳoӫʥ] Acknowledge Number OĪA]NOڭ̤W쪺Ӧ^ʥ]C
• Push function GpG PSH 1 ɭԡAӫʥ]sPǰewİϪ䥦ʥ]ߧYiǰeAӵLݵݽwİϺF~eCݥֱNƥ浃{BzC
• Reset GpG RST 1 ɭԡAܳsu|QWAӵLݵݲפT{C
• Synchronize sequence number GoNO SYN лxաI SYN 1 ɡANܵoeݭnDiPBBzA]NOnDإ߳suNAo SYN O۷n@ Flag I
• No more data fro sender (Finish) GpGʥ] FIN 1 ɭԡANܶǰeAMoX^AiӥiJ TCP ǰeפy{C
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• Window (ưʵ)GP̪wİϤjp@ӰѼơC

@
• Checksum(T{)GƭnѵoeݰeXeA|i@窥ʧ@AñNӰʧ@ȼЪ`boWFӱ̦oӫʥ]A|Aʥ]iҡAåBoe Checksum ȬO_۲šApG۲ŴNAYŴN|]ӫʥ]wglAiӭnD谵soeʥ]I

@
• Urgent PointerGܺƩҦbmC

@
• OptionGݭn client P Server PBʧ@{AҦp Telnet AnBznݪ椬ҦAN|Ψoӫwƫʥ]jpALAo٬O֥ΪI
@
AѤF TCP ʥ]榡AAӧڭ̽ͤ@͸̭XӭnTaIƹWATCP ҥHQ٬suɦViaǿAOaW쪺 Control Flag ӱʥ]XСAH Client P Server ݫإ߰_suCHUϬҡG
@
ϤBTCP ʥ]TV洤 @
bWϤASYN P ACK NO Control Flag } TCP ʥ]tTIClient ݻP Server ݦbgLFnDDʫإߡB^нT{ʥ]BAT{A̫إ߰_䪺fsuAѩ󬰤Fإ߰_̲תsuAݭniTʥ]nDPT{A]ڭ̤]ٳoӫإ߳sueBJyTV洤, Three-way handshakezFCoӰʧ@bإ߳suHΨ𪺳]w̭O۷nI
@


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UDP
@
UDP WOGyUser Datagram Protocol, ΤƬywzAUDP P TCP @ˡA UDP ѥiaǿҦA]LOsuɦV@ӾAoO]b UDP ǰeL{AҦpϤAݦbʥ]A|^Ц^ʥ] ( ACK ) oeݡAҥHʥ]èS TCP ʥ]YKҾCܩ UDP YƦpUҥܡG
@ TBUDP ʥ] Header T

UDP Source Port(16)					UDP Destination Port(16)
Message Length(16)					UDP checksum(16)
Data ...... Message

@
pWҥܡAUDP ʥ]ȴ UDP ϥΪf(port)AYҦΪTn TCP ֫ܦhAѩCӫʥ]jpOAҥH@ UDP ʥ]A򥻤WӻALүeǪ (Data/Message) N| TCP ʥ]Ӫh@ǡC~Aѩ UDP ʥ]ݭnݦ^ʥ] (ACK) AҥHǿtפW֤@IC֡A UDP ʥ]iaA]LAΩiaʭnDXAp@Unͪ DNS ǰeC
@
TCP P UDP bǿiaʡBǿqHζǿtפWOUuIAҥHUAΪXI
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ICMP
@
ICMP ٬Oy Internet Control Message Protocol zC򥻤WAICMP O@ӿ~P^A̤j\NOiHTOڭ̺suAAPsuTʡIL ICMP èSǰeOAݭnǥ IP ӶiǰeCICMP ۷hOiHP^AUO`X ICMP O (Type)G
@
|BICMP UOҥNNq

ON	OW	Nq
0	Echo Reply	N@Ӧ^H
3	Distination Unreachable	ܥتaiF
4	Source Quench	router tLɡAoOXiHΨoeݰ~oeT
5	Redirect	ΨӭsɦVѸ|T
8	Echo Request	ШD^T
11	Time Exceeded for a Datagram	ƫʥ]bYǸѶǰe{HyOɪAAOXiiӷӫʥ]wQT
12	Parameter Problem on a Datagram	@ ICMP ʥ]Ƥe~ɡA|^ШӷDѼƿ~T
13	Timestamp Request	nDeXɶTAΥHpѮɶtAHPBʨwnD
14	Timestamp Replay	TºO^ Timestamp Request Ϊ
15	Information Request	b RARP wΤeATOΨӦb}ɨoH
16	Information Reply	ΥH^ Infromation Request T
17	Address Mask Request	oTOΨӬdߤl mask ]wH
18	Address Mask Reply	^l mask d߰T

@
b ICMP ηAWNO ping P traceroute FAoӫOiHΨڭˬdӺDIOIOԲӥΪkAڭ̦b᭱`yLinux `ΫOzA~򪺤СC
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ʥ]Lo𷧩
@
ѤWAڭ̪DƪǰeNOʥ]oXPʧ@աIåBPʥ]W@˪Y ( header )A~Aʥ]Wq`|㦳|Ӱ򥻪TANO socket pair ̭쪺yӷPت IP HΨӷPتݪ port numberz CMաApGOiaʳsu TCP ʥ]A٥]t Control Flag ̭ SYN/ACK nTOInFA}lʤ@ʸASQyzrڡHIiHױ@ǥi঳Dʥ]Ab Linux tΤWOױʥ]OH껡Ӥ]O²AJMʥ]YWwgohnTAڴNQΤ@ǨPnӶiʥ]YRAåB]wRWhAo{YǯSw IP BSwfΪ̬OSwʥ]T(SYN/ACK)ANNӫʥ]LANO̰򥻪zFI
@
|ҨӻAjaD Telnet oӦAOMIA Telnet ϥΪ port number 23 AҥHAڭ̨ϥγnhRneiڭ̥Dʥ]ɡAuno{ӫʥ]تaOڭ̥D port 23 ANNӫʥ]ᱼhINO̰򥻪רҰաIhTڭ̷|bYy²zPy{ѺwzihI

FW쪺̰򥻪¦~Ao٥nͤ@Ӱ򥻪[A_h򪺥DW٬d߳]wժInFAڭ̪DqbWnMDɫAOQ IP өw}AӥH TCP/UDP/ICMP ƨӶiǰeAåBǰeL{ٷ|hʥ]TC`k@yܡAOa TCP/IP aڨӹFAҥHnD IP Aq~sWHζǰeơC
@
DOAqO̾ڤHݭnӫإߪALH IP o@Ʀrä㦳ӷPʡAY IP wgQ²ƬQiFAOHNOƦrSkڡIHISYAϥqDWٹIڴNNDWٻPL IP _ӡAӭnsWӹqɡAunDӹqDWٴNnFA] IP wgDW٤FIҥHH]eOФrDW١Aq]iHǥѹӧLnD IP AڡIuOҤjw߰ڡI
@
oӥDW (Hostname) IP tΡANOW Domain Name System (DNS) I]NOA DNS oӪAȪ̤j\NObiyDWٻPӥD IP z@wCDNS bҷO۷`QϥΨ쪺@wI|ӨҤlӻAڱ``|s_ꪺ WWW hݳ̷ssDAڤ@wݭnN_ꪺ WWW IP IUӶܡHIѧoAѩʳonAiN IP IUӡHILApGOnN_DW٭IUӪܡANehFINO http://tw.yahoo.com ܡHIӬJMqDu{ IP ӤwA]ڦbsWJFyhttp://tw.yahoo.comzɫAڪqN|ǥѦV DNS Dd tw.yahoo.com IP AANdߨ쪺 IP G^ڪsAڪsNiHǥѸ IP ӳsWDաI
@
o{FܡHڪqnV DNS Dd Hostname IP TI򨺳 DNS D IP Nnbڪq̭]wn~AåBnOJ IP AMڪqs DNS DhnDƩOHIb Linux ̭ADNS D IP ]wNOb /etc/resolv.conf oɮ׸̭աI
@
ثeUj ISP ѥL̪ DNS D IP L̪ΤAn]wȤۤvq DNS dߥDALApGzѰOFΪ̬OzϥΪҤèS DNS DOHISYAN]wعqHӳ̤j DNS DaI IP O 168.95.1.1 In]wn DNS AӤWsɡA~ϥΥDWٳIMNo@wݭnϥ IP ~WOIDNS OܭnALz]AԲӪzڭ̦b᭱yDNS A[]z̭ihԲӪIo̶ȴӤjI

rIu֤H¦ڡIͧF@ǰ򥻪[AۤUӴNO@oIAnqA۵MNݭnNҦqHysuCzs_ӡAo̫CNOyuBuΥ洫( Hub Switch )BdzwtưաIMաAѩܪC餣PAGup]|ҮtIo VBird Hثe̱`@p~ήax LAN ̭GuyPγsuzӶi满Coج[c򥻤WyNOH@ Hub Ϊ̬O Switch ߡAiӱNҦqs_zAHѦUӹq\Ioج[c̤juIb󰣿eIڭ̩UCX@ӫ²檺axPά[csuG
@


ϤCBPκsun

@


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򥻤G
@
bϤC̭Aǰ򥻪OHڭ̥ӽͤ@ͩwqaI ^_^
@
• Host ( D )GunOsbWDn]ơAXGiH٬D (HOST) CҦpA (server), Ѿ ( Router ), L, ׺ݾHΤu@, ٦LsuAiHQ٬O Host C
@
• Node ( `I )GsbWҦDu]ơAiH٬`IAҦpWϤC PC, ISP DAƾھ, 洫, AO node Iڭ̭n\ client P Server suɡAbosuWҦ node SD~IҦp洫nॿTu@AServer nണѥ`AȵCڭ̦biɡANOѤ@Ӥ@Ӫ Node ӵۤժI

@
• Client ( Τ )GVAoeXƯDʥ] host NiH٬O Client FI|ҨӻA Linux PC 3 VLAnDƮɡAoqNO client աIӷ Linux NAT AAV ISP jDnDƮɡAbɪ欰L]O Client IҥHLOܽA Client AȡAPɦpGLVLDnDơALN Client I
@
• Interface ( )G@wOdI|ҨӻAڭ̨ϥ ADSL ISP A|o@B~ ( ppp0 )AӤڤWOSw骺 ( O[cbdWաI )A~ApG[]@Ӻdh IP ]w ( IP aliases )A]|b@idWͦhӺI
@
• Network adapter, Network Interface Card, NIC ( d )GIoӫNOڪw髣I

@
• Server ( A )GDѪAȮɡAҦp WWW, FTP... A host NiH٬ Server FI

@
• Workstation ( u@ )G²檺ӻAunSѪAȪANiH٬u@FIҦp Windows PC1, Windows PC2...ALAƹWu@YҨӻA٬OtOCҦpYǴѫܱjjBODAӤ]|Q٬yu@zAYɥLMѺAȡI
@


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su򥻭nD
@
nFApGwsuwgإߤF_ӡAڪqngL Internet su컷ݪDɡAܤֻݭnǥT]wA~isuOHeXӤp`O¦]wAo̭nyLЪhOD]wɻݭn`NƶG
@
1. Linux ֤ߥ䴩dG

ڭ̦bey Linux pе -- ¦Dz߽gzLFAnw饿TL~u@Az֤ (Kernel) Nn䴩ӵw~A]NOAݭnw骺Xʵ{աIҥHoAХTwzʶRdOQ Linux Ҥ䴩AMܡAzNoVtӭnDXʵ{AMbۤv Linux tΤWsĶn~I
@
2. d㦳Xk IP HΥTѼƳ]wG

AӡAѩڭ̥ثe¦O IP ( Internet Protocol ) i淾q ( ѩo IP Ogѧ@~tΪn鵹AҥHS٬ n}( software address ) Aӥѫe¦ЫAڭ̤]Dn\sWANݭnӥDnѼƤ~GIP, Network, Netmask, Broadcast, GatewayAoǸƳnॿT]wbztΤWF
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3. ƫʥ]ǰeG

IשsWFALnuǿƱoݭnAѨW~쪺yʥ]榡zeաIʥ]ǰeݭnNTsuإ߰_ӡAӳsuإ߻P Socket pair AҥHڭ̥b Client ݦw˥T Client nApGO Server ܡANonҰʥTAȡAH}ҩһݭnsufAHΨӫإ߳suåBiƪǿoI
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4. gL`IB Router Gateway DG

nFAѩڭ̬Og Hub/Switch isAҥHڭ̪ʥ]Ƥ@w|gLoӸ`I~|ǰeXhIoӮɭԤTnQ@QA Hub n٬O Switch nHo̦򤣦POH̤jPӦ۩y@ɺCzPyCz[cWIMѩʥ]O socket pair ڭ̪ʥ]NiHǥѤ@ӤS@Ӫ router ǰeتaI
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ҥHA򥻤Wڭ̦bǰe@ӸƪɭԡALOAL]iHQo²INOG
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1. @~tΥ̾ڳn鵹 IP ӱNƥ]ݶǰeʥ]AҦp TCP ʥ]AWðOFӷPت IP P portF
2. ھګʥ]Wتa IP ơAøg W route table ӨoU@ router T( YbP@줺Ah router id )AMNưe router WhF
3. router 欰A̫eتaݪ PCAӹDz TCP ʥ]I

שiHӽͤ@͵w骺ܳFIC骺ܤ²ڡA]n̾ڱzSPtӶiܤ~nIUͤ@Ǥ²檺`NƶaI
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• uOPšG

̱`CMNOuաIثeDyuӬO RJ-45 YuFAܩ󦭴uhHPbqluDC]Pbqlṳjǿt׶ȹF 10Mbps AҥHwg֨FA]Uڭ̶Ȱw RJ-45 uӻCRJ-45 upUҥܡG RJ-45uOŪAӹ@axΤp~ϥΪ̦ӨAӿ CAT5 oӵŤ~nIIHu]ŤHOrI褣OLFܡHӺCOܭnAӥѩC餤]TNOqlաIѩqlTbiɭԷ|ͤ@ǹqϮ( o̫O cross talk )Ao cross talk N|vTӶǿ骺įIFקK cross talk zZAH̷QXFܦhkӸѨMLIҿתyu, Twisted PairzBδѫ̽yShielded, STPz\Au cross talk zZCAôɾ骺ǿt׭tqI Ө̾ڵP̳ŨӱNušIثe̱`ӴNO CAT5 o@ŰաI̤jǿqiHF 100 Mbps ӳ̤jǿZiF 91m OIҥHAЪ`NybܺuɭԡAܤֱzuŭnF CAT5 ~IzA_hYϱzdiHFǿq 100 Mbps AOuu 10 Mbps ɡAI̤jǿqN|Ȧ 10 Mbps I
@
• RJ-45 u(uPu)G

RJ-45 u@ 8 uAھڽuƦCǪPӱN RJ-45 رY榡AoرY 8 luƦCǤOpUҥܡG
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YW	@1@@2@@3@@4@@5@@6@@7@@8
568A	պ@@վ@š@š@@մġ@
568B	վ@@պ@š@š@@մġ@

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bC]OqlTAѩqlTݭnO@Ӱj~q(Ҧpt)AҥHoǰT۵MNݭnoInFAѩ]ƪPA]u}]|ۤPAҥHNoرYs@FC@uݨϥΦP@رY(Pɬ 568A ΦPɬ 568B)ɡAhٸӺuuAӦpGuݤOO 568A P 568B ܡANٸӺuyuIzC@ӻAڭ̳ϥΡyuzsqDP Hub/SwitchFLAqDnPt@qDϥκddsӤzL Hub/Switch ɡANݭnϥθu~IonI
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• dʨ̾ڡG

dʨ̾ڷMOyLinux 䴩dzĤ@uաInMܱzٱoۦsĶdXʼҲաAܶ˸Ct~AثeDydyqyiH۰ʤ 10/100 Mbps yqzA~ApGzDOwpnΨӬ[] Server AåByq٤pܡAdna٬OݭndNOIznҼ{OG
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1. wpj[]GpGzOQnϥαz Linux z[]jDܡAҦpCѧYɤWuHƳiFWʤHjAoӮɭԴNonn@IdաI]ndiH` CPU QβvAåBbtθ귽tHΨL귽t譱|AeyΪ̬O`IҥHR@n@I 10/100 Mbps 3Com or Intel dAOdU٤oI

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2. @aΩΪ̬OpyqGpGzߨSojAӬOƱiHnnDz Linux ӤwAåBϥΪO 512 Kbps ADSL tΡAIӦndzUNS˭nաIoӮɭԫKy 200~300 d( ɶqRҿתɥd ) NiHαoܶ}߰աIڥثe]OϥοɥdbڪJWOI
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٬ɥdOHoO]ӴլO RealTek X~ӫ~AӴժ Mark IɡAҥHNQq٬ɥdFI ^_^b Linux ̭AɥdҲլO 8139 OIڭ̦b᭱`|򤶲гI
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• Switch ٬O Hub G

nFAWPγsuϥܷA]F{bhbH Hub/Switch CAo̤tOH Hub/Switch ½Ķyu/洫zCHub ٤nzѡA򥻤WALȬONҦuLsb@_AèSҼ{L]I]ACqunsW Hub APıWNnsW Bus @˰աAҥH Hub O@ӡy@ɴCzIIyM̫Yz Switch rIH Switch q` Hub nQWD`hOHL̪\঳̤PH̰¦Pb Switch hF@ӥiHOW Switch Dd MAC P switch port Oиư( table )I]NOA switch |OL port P port sDd MAC Ao˦nBOHo˻nFAzPγsu줧@qbizsɭ(Ъ`NAzsDnOH MAC ǻH)G
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• pGϥΪsCO Hub ɭԡAҦso Hub WD|Ӽsʥ]F
• ӦpGϥΪsCO Switch ɡAѩW table wgOF MAC Port ơAҥHӫʥ]N|yzgѸ port ӰeXhتaDI
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ѩo˪YA]bi檫zsɭԡANwghFiಣͫʥ]IAFIҥHA Switch wgO@ӡy@ɴCzFI]WA Switch P Hub үӨyqγ\ۦPAO Switch oiHFnǿ\AΦbjAKKIMO Switch ΰաIo]O Switch |Q]rIAjդ@A Hub Mݩy@ɴCz@ءAM Switch XGiHݰOyD@ɴCzFI{b Switch ٥]tF Auto MDI/MDIX ۰ʧPOu\AҥH Switch sDduAרϥΥuθuA㦳 Auto MDI/MDIX Switch iH۰ʿOA٫oFϥΪ̭nʶRuɭԪxZOIҥHApGҼ{({bKy@I Switch ]C 1000 jvHFI)ʶR Switch O@Ӥ׳I
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• yqҶqG

SOdN@ƱANObz̭AyqObyyq̤pӸ˸mzұAӤOҦ˸myqIҥHbzʶRuBdBSwitch/Hub ]ƮɡAOݭn@֦ҶqҦtƪA̦nٯPۤvҬ۰tXAoˤ~FnftI

• OSI Chw@Ӻҫ ( model ) AëDwʳWwCoChwiHUnw}o@Ӱ򥻪ǫhF
• {¦O[cb TCP/IP oӳqTwWF
• Ƴsh̭nT MAC (Media Access Control)Ai٬w}A ARP Table iHΨӹ MAC Pn} ( IP ) F
• ǿϥ bit ӤO byte F
• bC譱A Hub @ɴCA]i|ʥ]IDAܩ Switch ѩ[JF port P MAC A]wgJAFʥ]IDA]NOASwitch äO@ɴCF
• Physical broadcast P Logical broadcast \णìۦPAsbCA Logical broadcast hDnwhn}isF
• IP 32 bits ҲզAFAHOСA]ন|դQi쪺ƾڡF
• IP Dn Host ID P Net ID ⳡA[W Netmask oӰѼƫAiH]wyzF
• IP uءANO Public IP P Private IP A½Ķ @ IP P p(ΫOd) IPAp IP PpѤiHs Internet WF
• C@DۤvѪAoӸѪWwFʥ]ǰe~|AbѪA̭n̬w]qTh ( Gateway/Router )F
• @ӻA@ḒѼӨƦGIP, Netmask, Network, Broadcast, Gateway F
• ثe`ƫʥ]榡 TCP/UDP/ICMP ATCP ǽTʥ]榡AzLhؽT{qӨϫʥ]iHǽTFتaAܩ UDP hLoǽT{A]ǰet׸֡C
• bD port Au root iHҥΤp 1023 HU port F
• DNS Dnتbi Hostname IP \F
• RJ-45 u̾ڱYuƦCAiuPuF

• ²z OSI ChwC@h\F
• b ISP ѪAȤAL̴ǿt׬ 1.5M/382K AаݳoӼƾڪ쬰H
• O MAC ( Media Access Control ) AMAC Dn\OH
• иOzs ( Physical Broadcast ) ALP޿s ( Logical Broadcast ) 򤣦PH
• Oʥ]IH|oͫʥ]IH
• ARP Table @άHpbڪ Linux ݧڪ ARP H
• ² Netmask @λPuIF
• ڦ@պ쬰G 192.168.0.0/28 AаݳoӺ쪺 Network, Netmask, Broadcast Uh֡HӥiHϥΪ IP ƶqPdUOh֡H
• ӤWDApGO 192.168.0.128/29 OH
• ڭnN 192.168.100.0/24 o C Class 4 ӤlAаݳo|ӤlnpܡH
• p[ Linux DWѸT ( route table )H
• TCP ʥ]W SYN P ACK лxNNqH
• OTV洤Hb@ثʥ]榡W~|TV洤H

eѦҥθѵ

b 2002/07 oXA۷hBͪߡA]qӵo{Fۤv~|@ǰ¦zסAuOP¦nB Netman SP ZMAN SɡIogub 2003/08/03 F۷jTת׭qAPӪ峹 ( Ws 2002/09 ) wg@w{תtFAƱ̦ͭpGɶܡAA\ŪAHM@ǰ򥻷I

• Study Area ¦Ghttp://www.study-area.org/network/network.htm
• Request For Comment (RFC) ޳NGftp://nic.merit.edu/internet/documents/rfc
• Hub P Switch gGhttp://www.study-area.org/tips/hub_switch.htm
• BBS Wݵ