Mail Transfer SMTP Specification SMTP basics

FTP Control ConnectionVery similar to SMTPSMTP was once part of FTP4 letter commands, plus parameters3 digit (+ message) responseMulti-line responses possibleSome responses contain information for softwareAuthentication commandsCommands to set optionsCommands to cause data connection setupCommands to cause data transfer to occurFTP Data ConnectionUsed for "File Data" OnlyFile Data includes process outputdirectory listingsHas MODE and TYPEMODE - format of data transferSTREAMPAGEBLOCKTYPE - interpretation of data transferredASCIIIMAGELogical Bytes (with byte size)Designed to allow like systems to be ableto transfer fileswithout reformatting at either endBut to also allow dissimilar systemsto exchange meaningful informationCreating Data ConnectionsClient must tell server location of other serverEven if other server is the clientAnd/or must tell other server to expect incoming connectionEasy if other server is clientDoneBy requesting address & port numberat server to be target of connectionBy sending address & port numberto create a connection