计网实验problem-13

problem13answer:1.Forprivatecommunication,aprogrammercreatesapairofapplicationsthatcommunicateovertheInternetwiththeintentionthatthepairisforprivateuse.CodecanbewrittenwithoutwritingaformalprotocolspecificationForstandardizedservice,manyprogrammerswillcreateserversoftwaretooffertheserviceorclientsoftwaretoaccesstheservice.inthiscase,applicationprotocolmustbedocumentedindependentofimplementation,thespecificationmustbepreciseandunambiguous.Thesizeofaprotocolspecificationdependsonthecomplexityoftheservice.2.(ICANN).MostUScorporationschoosetoregisterundercomdomain.6.ForDNS,Theuseofaliasespermitsanorganizationtochangethecomputerusedforaparticularservicewithoutchangingthenamesoraddresses.Italsoallowsanorganizationtoassociatemultiplealiaseswithasinglecomputer.7.Emailsoftwareisdividedintotwoconceptuallypieces:anemailinterfaceapplication;amailtransferprogram8.SMTPmeansSimpleMailTransferProtocol.9.TwoMailAccessProtocolsarePOPIMAP.10.MIMEmeansMulti-purposeInternetMailextensions.TheMIMEstandardextendsthefunctionalityofemailtoallowthrtransferofnon-textdatainamessage.