权威例句
Simple Mail Transfer ProtocolSimple Mail Transfer ProtocolRfc821: simple mail transfer protocolSimple mail transfer protocol (rfc 2821)Simple Mail Transfer Protocol (SMTP) Service ...RFC 5321:Simple Mail Transfer ProtocolA comparative study of Simple Mail Transfer Protocol (SMTP), Post Office Protocol (POP) and X.400 Electronic Mail ProtocolsSimple mail transfer protocol, Request for Comments (Standard) STD 10, 821A No Soliciting Simple Mail Transfer Protocol (SMTP) Service ExtensionRequest for Comment (RFC) 2821: Simple Mail Transfer Protocol
