【正文】 End of the string. In the case with parameters, the mand itself is SP and the parameters separately, if not directly, and with parameters CRLF Connection. Mailbox syntax and receiving sites must be consistent with the form. SMTP mands and responses are discussed below. Send operations involving different data objects, their mutual connection by different parameters. Reply Path parameter is the MAIL mand, the forward path is the RCPT mand parameter, the message date is the DATA mand. These arguments or data objects must follow the mand. This model also requires a different buffer to store the objects, that is, there is a path back buffer, a forward path buffer, the contents of a message buffer. The mand generates its own specific buffer, or to one or more of the contents of the buffer is cleared.An important feature of SMTP is its ability to transmit messages in the Relay, Transfer Service provides interprocess munication (IPCE), and this environment may include a network, several networks or a network subnet. Understand that the transmission system (or IPCE) is not a one to one very important. Process and other processes may be directly through the munications of known IPCE. Mail is an application or interprocess munication. Mail can be connected in different IPCE the process of internetwork mail delivery. More specifically, mail can be a host of different network relay transmission.Known as the Simple Mail Transfer Protocol SMTP (Simple Mail Transfer Protocol), aim to provide efficient and reliable message transfer. An important feature of SMTP is its ability to transmit messages in the Relay, that the message can be different relay hosts on the network transmission. Work in two situations: First, transmission from the client to the server。 it has the following key differences:(1) It is generally useful only within a trusted enclave(2) It protects the entire envelope of a message, not just the message39。說到這，為了標準化這個協(xié)議的狀態(tài)和地位，就必須提及目前最新的“Internet 官方協(xié)議的標準”(STD1)。當接收者收到全部郵件后會接收到特別的序列，如果接收者成功處理了郵件，則返回“OK”應(yīng)答。這些參數(shù)或者數(shù)據(jù)對象必須跟在命令后。更特別的是，郵件可以通過不同網(wǎng)絡(luò)上的主機接力式傳送。這個文檔用到的協(xié)定在以下的這些例子中，C和S分別表示客戶端和服務(wù)器。如果服務(wù)器并不支持所需要的認證協(xié)議，就會用504的回答來拒絕這個認證命令。它發(fā)送一個零長度的初始化回答作為一個=符號。服務(wù)器MUST命令將拋棄所有的不是通過客戶端而得到的認知，比如不是通過SASL本身而獲得認知的EHLO命令的論點。討論：認證中一個可選的參數(shù)的郵件來源 命令允許一個協(xié)同工作的代理與一個單獨的消息就行通信在一個被信任的環(huán)境里。在這種情況下，服務(wù)器能做的僅僅就是解析有效的認證命令的參數(shù)，并把它提供給任所有使用認證擴展的認證機制的服務(wù)器，并遺棄無效的參數(shù)。除了那些被標注的以外，所有的按字母順序排列的特征都是適合于固定場合的。認證命令的參數(shù)就可以阻止這種攻擊。越來越多的人在使用它。如何幫助用戶從互聯(lián)網(wǎng)中獲取有益的信息而避免不良信息污染已經(jīng)成為當前網(wǎng)絡(luò)研究領(lǐng)域需要迫切解決的一個問題?；ヂ?lián)網(wǎng)的高速發(fā)展已經(jīng)使其成為世界上覆蓋面最廣、規(guī)模最大、資源最豐富的信息網(wǎng)絡(luò)。另外需要說明的是，安全問題的考慮在SASL說明里面也有提到。因此客戶端和服務(wù)器都必須拋棄在SASL之前獲得的所有消息。這表示服務(wù)器需要為了執(zhí)行被請求的操作，需要一個認證。服務(wù)器將把郵件列表的擴充視為一個新的任務(wù)，認證命令加入到郵件地址列表中，或者在中轉(zhuǎn)這些消息到列表簽署者的時候管理郵件列表。只要由認證機制產(chǎn)生的受客戶端和服務(wù)器支持的命令和響應(yīng)，客戶端和服務(wù)器端須支持，而不依賴于服務(wù)器或者客戶端的、可能存在于協(xié)議實現(xiàn)的某些方面的行長度的限制。如果SASL認證交互穿越了一個安全層，將會通過一個有用來中止認證交互的CRLF來產(chǎn)生效果，而服務(wù)器也通過一個CRLF做出正確的響應(yīng)。對認證命令來說，可選的初始化響應(yīng)建議是用來在使用認證機制時保持一個往返的回程,認證機制的定義中此建議不發(fā)送任何數(shù)據(jù)。如果郵件服務(wù)器支持這種認證機制，它就會執(zhí)行一個認證協(xié)議來認證并識別郵件用戶。簡介這個文檔定義了簡單郵件傳輸協(xié)議服務(wù)的擴展（E簡單郵件傳輸協(xié)議）并且說明了一個簡單郵件傳輸協(xié)議客戶端可以為服務(wù)器指定一種用來執(zhí)行與認證協(xié)議的交換，并且隨意地穿越并發(fā)的協(xié)議之間交互的安全層面的認證機制。郵件是一個應(yīng)用程序或進程間通信。發(fā)送郵件操作涉及到不同的數(shù)據(jù)對象，它們由不同的參數(shù)相互連接。簡單郵件傳輸協(xié)議發(fā)送者再發(fā)出接收命令確認郵件是否接收到。 can reduce unnecessary transmission of information so that the network more smoothly。s identity in the addrspec in an AUTH parameter when relaying the message to any server which supports the AUTH extension.If the server does not sufficiently trust the authenticated identity of the client, or if the client is not authenticated, then the server MUST behave as if the AUTH= parameter was supplied. The server MAY, however, write the value of the AUTH parameter to a log file.If an AUTH= parameter was supplied, either explicitly or due to the requirement in the previous paragraph, then the server MUST supply the AUTH= parameter when relaying the message to any server which it has authenticated to using the AUTH extension.A server MAY treat expansion of a mailing list as a new submission, setting the AUTH parameter to the mailing list address or mailing list administration address when relaying the message to list subscribers.It is conforming for an implementation to be hardcoded to treat all clients as being insufficiently trusted. In that case, the implementation does nothing more than parse and discard syntactically valid AUTH parameters to the MAIL FROM mand and supply AUTH= parameters to any servers to which it authenticates using the AUTH extension.Examples:C: MAIL FROM : e=mc2 AUTH=e+3Dmc2S: 250 OK6. Error CodesThe following error codes may be used to indicate various conditions as described.432 A password transition is neededThis response to the AUTH mand indicates that the user needs to transition to the selected authentication mechanism. This typically done by authenticating that once using the PLAIN authentication Authentication mechan