TCP/IP Network Administration
`Second Edition
`
`Craig Hunt
`
`Cambridge
`
`O’REILLY”
`© KAMbookeExhibitNo4016/1 110
`Page 1
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`Facebook's Exhibit No. 1016/1116
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`TCP/IP Network Administration, Second Edition
`by Craig Hunt
`
`Copyright © 1998, 1992 Craig Hunt. All rights reserved.
`Printed in the United States of America.
`
`Published by O'Reilly & Associates, Inc., 101 Morris Street, Sebastopol, CA 95472.
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`Editor: Mike Loukides
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`Update Editor: Gigi Estabrook
`Production Editor: Nicole Gipson Arigo
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`Printing History:
`
`August 1992:
`
`First Edition.
`
`March 1993:
`
`Minor corrections.
`
`September 1993: Minor corrections.
`
`January 1994:
`
`Minor corrections.
`
`May 1994:
`
`Minor corrections.
`
`January 1998:
`
`SecondEdition.
`
`Nutshell Handbook and the Nutshell Handbook logo are registered trademarks and The
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`This bookis printed on acid-free paperwith 85% recycled content, 15% post-consumer waste.
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`ISBN: 1-56592-322-7
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`lable of Contents
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`PHOFACE oooeciceccccccecis cece tsetse cse esse teateeeeetissssssisiisitvesssstestuetiesenterenieseesen xt
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`Te Overview Of TOPLIP iiciciccccccccccccee tests tes es issesstsseasesesitentursresssesereneteeses 1
`
`TCP/IP and the Internet oo... ccccccccccsccsscescsscescnecssesscstestssvsseseeseeasesessaesavaaens 2
`
`A Data Communications Model o..ccccccccecececeseecesscessesessesessevreeneeertreeniesens 5
`TCP/IP Protocol Architecture occ ccccceceseseescsessseresssessescssecveceesivstsissrerevaveres 8
`Network Access Layer o.cciccccccceccccsseetsessesestiessecstsssesersevsteensestssitesessvecsssaseees il
`Intermet Layer coe cccccecceeceereeeesseescsssescsesserssesesensessesvsesenstevsisesenerseres il
`Transport Layer cece ccc ceten en seenecsersessessstestisettatsasetersenisersiesiees 17
`Application Layer occ ciccccceeseeneceescieesnsesseetesesecssssesssteutersseevesieersitetieenees 21
`SUMIMALY occ erect ce cect reneeneeneetedeeetestesteeseteiseasiesstsassesitsiteitersesseetnsenes 22
`
`2) Delivering t@ Data ooiccccccccccccccccesiestessisssssssvsvssevssssessesssesversietsussevsevsaes 23
`Addressing, Routing, and Multiplexing .0..cc.ccccccccccesesessrseeesssneesteeseserees 23
`The TP Address oie ccccecccesesesevevsesscatseceecsteesscscerssereveevsvevivaveetavivasersesseses 25
`SUDNEES oo ccc ceccteeeesesesessscstsesssssesesensussessssnsesvsvscsssisssusiuevavevevevevesevavaneres 31
`Internet Routing Architecture occ cccccccesecscseccsecsscstesseevsusscsvssuecevsveaseneeete: 34
`The Routing Table oc ccccesesesseceeessescscscsessscstsvspsusitevevevevevevevevensesesss 36
`Address Resolution ooo. cccccssessetesscsesesssesesescsessecrsscstevsvssseevsvsvsvevevevsvecers 39
`Protocols, Ports, and SOCKetS occ cesecccucececeevssessessesessevsseusesstevievesecstens 42
`SUIMIMALY occ ce cece cesreerenevssseetsesassessessseessssacsesssssesestersecstarereesvessecissavanens 47
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`
`
` vi Table of Contents
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`Bi
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`N@tWworR SCrvices iiiiiccccccccccccseesississessisssssssesssetsscsereestretsessesssresressessesneses 48
`
`Names and Addresses occ iiccccccessesessessessessessecstsesesecessssssesseetisreeserscevienes 49
`The Host Table oi. cccccccssecsesessecscseessesssesssssecstvsusrssssesscestasversessanerssesrens 50
`Domain Name Service icc ccisecceecscerseescessesseeessssascasscesscacsascssenssensceversaveas 52
`Mail Services oie cscceseenecseesseeaetsessctessasessasesssiesssecseuesssvseaeaevinen 60
`Configuration SCrvers occ ccccessvscsscscsetetecsecscsscsscscetvscevsssseesvesssssvessavectensveteres 71
`Bootstrap Protocol ....cccccccccccseseccsscssssecsssccssseccussecceserecereseutrseeusseetsatestssrseeens 73
`File and Print Servers ooo. cceccccccccsesesscsecssesscsecssestessessvssccevatvicaevsevsevanveseeatees 76
`SUITUMALY occ cece ene ccsensceeecsenecseseaeeaerseessessesssesescascassenscnecnitesseniienssetertate 78
`
`AS GEN SEATON oie ccc cee eecs cess tesstessssvesvessessvessssvsssetiusasesisessisiuesetesavestees 80
`
`Connected and Non-Connected Networks ......cccccccccscccscesceccevecccecseeseeeerees 81
`Basic Information occ ccccccccecccessesesenscaesetecsecsesecssesssseecsevsssssessressesvatssersnsesnsseres 83
`Planning ROUocc eceeeeeneeensnsesesenecsesssenseresessssssscetsrstetstrsvevsvssesseenes 91
`Planning Naming Service 0... cccccccceecscscseescsecsenscsessescsesssssssessescssseereceusveneeeees 94
`Other Services voici ccceccceeeesesseeessvssseseesescassssssessvssessessvssssesissscertecsavaesavseeatees 97
`Informing the USers o.occccccccccscccccssscsscsscstesecccsssesccssvsscesvsevsrvsenssersescarsaesees 100
`NECCOMAQ cer cecseeetseseetereeetereeniessee vaseesaeeveeeeeeecseetsaeerseseneesteesesaees 102
`SUIIMATY occ ccc cece cece teciresstecensnecnesteseciessastaccssesserssssatserstesericaesetes 104
`
`52
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`BASIC CONFIQUVATION oie ees testss eesti sessesssesesuesiesserseseitstens 105
`
`Kernel Configuration 00... cccccccceccccetectessisetsesessssecssssterestsssstntessissrenssesieass 105
`Linux Kernel Configuration. ooo. ccccccccceccssesscsseseesescrsessscstesestssvsevseveseeveres 106
`The BSD Kernel Configuration File oo... cccccccccececsesecsecsecserssseetestenseecssees 112
`The Internet Daemon o.ccccccccccccsscsssestssssetecsecacseesssecsecassavssssvsssevssevsvereecsees 118
`SUIMIMALY occ eceeececenereteeecneecneeeeteeeeeeetesseststecssesssaeesssecsssuvaterueeninenayeeatenss 121
`
`6. Configuring the Interface .oocccccccccccccccccccccessvesssesssessssssisssvessesssetsees 123
`‘The ifoonfig Command oc cccccccccccsccceescssseccsssessvecsecsessssaserstesvstssesernensses 123
`TCP/IP Overa Serial Line cc cccccccscscceenceeeeeeeen cent eeeentenneeniees 137
`Installing PPP oie cece tteceesetscsessesseeescstesseescsssitessssssseassscsesstssssssrees 140
`Installing SLIP woo. ecesccesessscsessesesessesevasssssseasssesesstessacseetsevavstissecseares 153
`SUITIMIALY eect ect re ect eccneeenneeneenisesneesieesstecteescneeenestreitiesseesensas 162
`
`7?
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`CONFIQUVING ROUcece ccc ccccccccceessscseesescesneeteeiesesiseteetsinsieeersenseries 164
`
`Common Routing Configurations oo. ccccccccscececsecsersecessecssnscrseneveseseres 164
`The Minimal Routing Table oo... ceceneneeeteetetsesesseersverserseeteenes 165
`Building a Static Routing Table oc cc cccceceeeeeceetetiecsesecsetassesseseesvicesenes 167
`Interior Routing Protocols wo... eccceceeeceeeeeeeeecsssecsecesecvssecsseuseseievteeseneens 173
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`Table of Contents
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`vit
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`Exterior Routing Protocols .....cccccccccscccccsesesssscecteeceveversecestnssseesecevtssneceres 184
`Gateway Routing Daemon cc eee ete ece ee eteetseeeteseteeetsttsssesstesereeeeen 187
`Configuring gated ce eececeenseeeeeeteneeuseettececseseeetstessststesvitsviesiensees 189
`SUITIDALY eee cere e etree reece ties e Cee cneettieFeetiabtnsdaetensaaareniaes 200
`
`Configuring DNS NAM SCrvile ooicccccccccccccsscssvesscesescsssssessescessesveses 202
`
`BIND: UNIX Name Service .oicccccccccecccseessscsseseecsassetsscssesssssvsesnaversuvrsenvrees 202
`Configuring the Resolver .o.cccccccccccccseesesscssesvssesvscsssesesssesevseetteseetseseesteaess 205
`Configuring MaAMed oo cece cccce sees stecsesececscscsesesesssesererseveveenseesersreaveeeevenes 208
`Using nslookup iicccccccceceeeesescsesececseecsesscsscssecsnsssevssesssssssssrssaveesserevavaraees 221
`SUITIMNALY iscccccecccccecececenscneeneseeeneeseessssasssecssvaseesssessssteasssceseasssscesvesuistareaeeets 225
`
`Configuring Network SCrvers i.ccccccccccccccecsscssessccssescssessitevsssetissees 226
`
`The Network File System ooo ceccceeetesestestesesesesestecstetseecsvevsererersevereens 226
`Line Printer Daemon woo. eceseteessetsesesstescsessseetiseseenetssesesreviey 240
`Network Information Service .o.cccccccccccscccscscesssessesssesrsevevseteseststerevansees 245
`A BOOTP Server once cccccccceetecssensenseseesesssesecatssesessesevirssesinassete tene tenes 250
`DHCP oie ccc ccccecceetseeseseeseessssessassessasceevsteusssssevsssivaesstsestecseteesattansanvatens 258
`Managing Distributed Servers oo... ccccccccccessecsesstesessesssscsessecsseseravcrseevertestans 263
`Mail Servers oii ccicceesecsseeseseceeseststsevaesevevssecsscecescersessssasavsavavaneseavenseeaves 266
`SUMUMALY cece ccc ccrcceseceeeseessessesssesessasssessssasvaterserseseevsseseivsavarevavereeesaeeas 269
`
`10:
`
`SONAMAI ooo. ciececccccccccs cesses tes etsteseesitssstistitessussasessissetssesectiesevseetiusveteeseen 271
`
`Sendmail’s FUNCHON ic cccecssesesesetscsesesecsesssesscscseecssstevisresevivieeesereneesseenes 272
`Running sendmail as a Da@MON o.....cccccccccscccceecscsereereeevsecseraeeatssestsevsees 273
`sendmail Aliases icc cccceceeeeseseneesesrsecsceescsesesssssessvsestevssesensavevausetenensees 274
`The sendmail.cf File co.cc cccccscsssessessssssesessscsescscscscsvsesereresievenveseensessaveeens 276
`sendmail Configuration ooo ccccccccccecsccescseecacssscsecsssesrsesescsssesvevsvssuevseasereavenss 283
`Rewriting the Mail Address ooo. ccccccccecsecsccscseeseseseseescssssssssevscessrsevevtecsataes 295
`Modifying a sendmail.cf File 0c cccccceccsesscetecscsvscsesessssssesssvsceversesevaveevenes 304
`Testing sendimail.cf oo. iesecccccecseccecersceesuscesassesssessesersseseesiseventeereerenses 308
`SUIMIMALY ccc ecccce ee cneeeeseeeessasssesseessissussessevssuesssssvscseseuvscesseversrssavesnesneveteaes 318
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`11:
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`Troubleshooting TCP/IP o..ccccccccccccccscccccsssccsssessstssesssieteJesceeevseeeeeneneeees 319
`Approaching a Problemocc ccccecccssesseseeessseeesssusrscsestevsessersasivteserveseevacens 320
`Diagmostic TOMS oo. cccecsccssesscsscsceecsecsesrtescsessscsstsssesesvseueutasssaesasavsateanas 322
`Testing Basic Comnectivity occ ccsesesetececacsescetsesessitessressviveviearsasisens 324
`Troubleshooting Network ACCESS oo... ccecccccccccscsesseseesessusvsevssestvasessestestessvecees 328
`Checking Routing occ cccccccccsssssssestsssessssssesvsesussessesessevsuevsvsvsssvavseseetenenes 335
`Checking Name Service ooccicceccssscsssescsssesesseesesvsnsusesscsusessresvavevnesevestevses 341
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` viti Table of Contents
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`Analyzing Protocol Problems oo.ccccccccccccccsssesecsecssesesessvecescestevececeseeceeceeee. 349
`Protocol Case Study oicccccccecesssssssesesssesessssscstacsevsvssesevsvststavssieavevevessveesesvies 352
`Simple Network Management Protocol
`.o.ccccccccccscscccscssesesvesesescsvssescaresesvevevens 356
`SUMIMALY eee ccesesecsesesssssssstescescsstssevepstcsusassaansassesvstavsestitavittevstescesses 361
`
`12: Network SCCULUY oocecccccccccccessssssscssssecsssietsssisessriessiictsiitssisssssssesessees 362
`Security Planning o...cc ccc sessseseesesescscsvecscsesssssvsesssssvetststusseaeevevavevecenes 363
`User Authentication occ cccccccsssssesscsssrsesssnsvsvscseasevscssavscerssseaeavavevevsveveves 368
`Application SECULtY oii ceceseeesssessesscstsusssevsticessesesssevavsvaveseatsvestavaveveee 384
`Security MOMILOTIN oe eee ce tesecessececesscesecessvevsvacsesestavsesevatavscavarsersvevsnes 385
`ACCESS CONULOL occ ccc csesesesesesetetsesscseversasvitstvevsereasstterertatassavareesessenes 393
`ENCryption occ cc csesesesessetetesseseesecsvecessevssesvecsvsevavsussetsavavavecstavscitvevsees 396
`Firewalls oo... cscssesesssesesesescesssesesesssssvscsssssatavssavavsususaratavsveveseaversecsvevees 398
`Words to the Wis ooocccccccccecccccscesseseersesesesevsevscvivrsetestetesvereteciceetececesce 403
`SUMIMALY ccc ci ceccneesesesesesevssscevscssssesersasusvavssausrsuesavevetensevsvavecsessseseeseecenee 404
`
`13: Internet INfOrMation RESOUPCES ooocccccccccccccccccccsccccsccsceccescesceeccecescecen. 405
`The World Wide Web oicccccccccscsecssscscscsrssesesvsvsustersusavstatssessseavarsucstseeseeees 405
`ANONYMOUS FTP oc ccceeneeeseeseetsecsecssscvesscsevecseserveseussvettavstsevavanseaneses 408
`Finding Files occ ceccccscsesssnesseecscscsescevevsesersessesersnsssuaressvevsssavavevececeees 413
`Retrieving RFCS ccc cscsceseseseseessssesestesssecscssvsvscsvsesvavseavssatsusttatieetenvess 417
`Mailing Lists occ ccs eseseeesssssssessscssssstssstucscerssvevsvsvacssesasetsnscansvavevsvavavevees 420
`The White Pages oo... cccccsscsestessesesssssestesescssusscsssesstsusevsreavateressesteesscevees 423
`SUMIMALY eee ccc ccccceseeeseessesessssssesesecsssvscsssvsvscititavasersvaversvatenstevevavavevsesees 428
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`Al PPP TOUS ooo cccccscssssssssssssessssesessesvsseovisseretssetsvavasvesssieessacsssiseseseesesesa 429
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`Br A BatCd RESCPENCE ooeiiieicceceocsecescccssessvsssesssessssssistsvessisssissssisssisessesseeesees 449
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`Cr A MAMOCA REPCLENCE ooieeceeccccccccccccsssvssevsssvesseesseessessresssisssisssessseesssesseseessees 497
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`Dz A ADCPd RESCVENCE oooceeicccccccccccsecesvsesesssssvessessecsisssessesssessesssesesesesesssesseen 519
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`Er A SENAMALIL REFCVENCE ooociiecccccccccccecccccsescsssessessssssesssessisssessisssesssesssessees 532
`Fo Selected TCP/IP HeQders oceccccccccccccccccscccscsscesssesssvsssestsvsssessriessseseseesses 583
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`TAO accesses cece esseeesesevsessistiisssssssressressressunsestessauasistsiesetsressereseesees 589
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