Virtual Private Networks: Turning the Internet Into Your Private Network

Historically,onlylargecompaniescouldaffordsecurenetworks,whichtheycreatedfromexpensiveleasedlines.SmallerfolkshadtomakedowiththerelativelyuntrustedInternet.Nowadays,evenlargecompanieshavetogooutsidetheirprivatenets,becausesomanypeopletelecommuteorloginwhilethey\'reontheroad.Howdoyouprovidealow-cost,secureelectronicnetworkforyourorganization?Thesolutionisavirtualprivatenetwork:acollectionoftechnologiesthatcreatessecureconnectionsor\"tunnels\"overregularInternetlines--connectionsthatcanbeeasilyusedbyanybodylogginginfromanywhere.Anumberofproductsnowexisttohelpyoudevelopthatsolution.ThisbooktellsyouhowtoplanandbuildaVPN.Itstartswithgeneralconcernslikecosts,configuration,andhowaVPNfitsinwithothernetworkingtechnologieslikefirewalls.ItcontinueswithdetaileddescriptionsofhowtoinstallanduseVPNtechnologiesthatareavailableforWindowsNTandUnix,suchasPPTPandL2TP,AltavistaTunnel,CiscoPIX,andthesecureshell(SSH).NewfeaturesinthesecondeditionincludeSSH,whichisapopularVPNsolutionforUnixsystems,andanexpandeddescriptionoftheIPSecstandard,forwhichseveralvendorshaveannouncedsupport.Topicsinclude:HowtheVPNcomparestootheravailablenetworkingtechnologiesIntroductiontoencryption,firewalls,theIPSecstandard,andothertechnologiesthatletVPNsworkPointtoPointTunnelingProtocol(PPTP)andL2TPTheAltavistaTunnelTheCiscoPIXFirewallSecureShell(SSH)Maintenanceandtroubleshooting,