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8HowtotroubleshootconnectivityissuesinSQLServer2000ChrisTull,MicrosoftHelpandSupportThisarticlecanhelpyoutoresolveconnectivityproblemswithMicrosoftSQLServer2000.Thisarticlecontainsdescriptionsofcommonconnectivityproblemsandthestepsthatyoucantaketohelpresolveyourconnectivityproblems.SQLServer2000supportsseveralmethodsofcommunicationbetweentheinstanceofSQLServerandtheclientapplications.IfyourclientapplicationandtheinstanceofSQLServerresideonthesamecomputer,MicrosoftWindowsinterprocesscommunication(IPC)components,suchaslocalnamedpipesortheSharedMemoryprotocol,areusedtocommunicate.However,whentheclientapplicationandtheinstanceofSQLServerresideondifferentcomputers,anetworkIPC,suchasTCP/IPornamedpipes,isusedtocommunicate.SQLServer2000usesNet-Library,aDLL,tocommunicatewithaparticularnetworkprotocol.AmatchingpairofNet-Librariesmustbeactiveontheclientcomputerandtheservercomputertosupportthenetworkprotocolthatyouwanttouse.Forexample,ifyouwanttoenableaclientapplicationtocommunicatewithaspecificinstanceofSQLServeracrossTCP/IP,theclientTCP/IPSocketsNet-Library(Dbnetlib.dll)mustbeconfiguredtoconnecttotheserverontheclientcomputer.Likewise,theserverTCP/IPSocketsNet-Library(Ssnetlib.dll)mustlistenontheservercomputer.Inthisscenario,theTCP/IPprotocolstackmustbeinstalledonboththeclientcomputerandtheservercomputer.AfteryouinstallSQLServer2000,youcanconfigurethepropertiesoftheclientNet-LibrariesbyusingClientNetworkUtility.YoucanconfigurethepropertiesoftheserverNet-LibrariesbyusingServerNetworkUtility(Svrnetcn.exe).TheserverNet-LibrariesareinstalledduringtheinstallationoftheservertoolsinSQLServerSetup.However,someoftheserverNet-Librariesmaynotbeactive.Bydefault,SQLServer2000enablesandlistensonTCP/IP,namedpipes,andSharedMemory.Therefore,foraclienttoconnecttoaservercomputer,theclientmustconnectbyusingaclientNet-LibrarythatmatchesoneoftheserverNet-LibrariesthatiscurrentlybeingusedbytheinstanceofSQLServer.ForadditionalinformationaboutSQLServercommunicationcomponentsandNet-Libraries,seethefollowingtopicsinSQLServerBooksOnline:•CommunicationComponents•ClientandServerNet-Libraries•ManagingClientsTroubleshootconnectivityissuesMostoftheconnectivityissuesthatyoumaynoticeinSQLServer2000occurbecauseofproblemswithTCP/IP,Windowsauthentication,oracombinationofTCP/IPandWindowsauthentication.9ImportantBeforeyoustarttotroubleshootconnectivityissuesinSQLServer2000,makesurethattheMSSQLServerserviceisstartedonthecomputerthatisrunningSQLServer.VerifyyourDNSsettingsThenameresolutionprocessinDomainNameSystem(DNS)isusedtoresolvetheIPaddresstothenameoftheinstanceofSQLServer.Ifthenameresolutionprocessdoesnotworkcorrectly,theinstanceofSQLServerisnotreachable,andyoumayreceiveoneormoreofthefollowingerrormessages:SQLServerdoesnotexistoraccessdeniedGeneralNetworkErrorCannotGenerateSSPIContextToverifythatthenameresolutionprocessisresolvingthecorrectserver,youcanpingtheserverbyusingtheservernameandtheIPaddressoftheserver.Todoso,followthesesteps:1.ClickStart,andthenclickRun.2.IntheRundialogbox,typecmdintheOpenbox,andthenclickOK.3.Atthecommandprompt,runthefollowingcommand:pingServerNameNotetheIPaddressthatisreturned.4.Atthecommandprompt,runthefollowingcommand(whereIPaddressistheIPaddressthatyounotedinstep3):ping–aIPaddressVerifythatthecommandresolvestothecorrectservername.Ifeitherofthespecifiedcommandsarenotsuccessful,timeout,ordonotreturnthecorrectvalues,theDNSlookupisnotworkingcorrectlyortheproblemoccursbecauseofothernetworkingorroutingissues.ToseeyourcurrentDNSsettings,runthefollowingcommandatacommandprompt:ipconfig/allToworkaroundthisproblem,addanentryfortheservertothe%systemroot%\system32\drivers\etc\hostsfileontheclientcomputer.YoucanalsoworkaroundtheproblembyconnectingtotheserverbyusingtheNamedPipesNet-library.VerifytheenabledprotocolsandaliasesConnectivityproblemsmayoccurifthealiasontheclientcomputerissetincorrectly.YoucanviewthealiasesbyusingClientNetworkUtility.Todoso,followthesesteps:1.StartClientNetworkUtility.IftheSQLServerclienttoolsareinstalledonthecomputerthatisrunningtheclientapplication,followthesestepstostartClientNetworkUtility:a.ClickStart,andthenpointtoPrograms.b.PointtoMicrosoftSQLServer,andthenclickClientNetworkUtility.IftheSQLServerclienttoolsarenotinstalledontheclientcomputer,followthesestepstostartClientNetworkUtility:a.ClickStart,andthenclickRun.b.IntheRundialogbox,typecliconfgintheOpenbox,andthenclickOK.2.IntheSQLServerClientNetworkUtilitywindow,clicktheGeneraltab,andthenenablealltheprotocolsthatyouwanttouse.NoteYoumustatleastenabletheTCP/IPprotocolandthenamedpipesprotocol.103.ClicktheAliastab,andthenverifythealiasesthatareconfiguredfortheinstanceofSQLServer.4.VerifythepropertiesofthealiasestomakesurethattheservernameorIPaddressandtheprotocolareconfiguredcorrectly.Youcancreateanewaliastotesttheconnectivitybyusingtheservername,theIPaddress,orevenbyusingadifferentprotocol.NoteEarlierversionsofMicrosoftDataAccessComponents(MDAC)haveadifferentuserinterfaceforClientNetworkUtility.Therefore,ifyoudonotseetheoptionsthatarelistedinthisarticl