SMTP (Simple Mail Transfer Protocol) : 电子邮件从客户机传输到服务器或从某一个服务器传输到另一个服务器使用的传输协议。 SMTP 是请求/响应协议，命令和响应都是基于ASCII 文本，并以CR 和LF 符结束。响应包括一个表示返回状态的三位数字代码。-SMTP (Simple Mail Transfer Protocol) : E-mail transmission from the client to the server or from a server to another server transmission of transmission agreements. SMTP is a request/response agreements, orders and responses are based on the ASCII text, and to meet CR and LF end. Response includes a return to the state said the three-digit code.