SMTP

Simple Mail Transfer Protocol

标准文件

RFC 821 SIMPLE MAIL TRANSFER PROTOCOL Jonathan B. Postel August 1982 Information Sciences Institute University of Southern California 4676 Admiralty Way Marina del Rey, California 90291 (213) 822-1511RFC 821 August 1982 Simple Mail Transfer Protocol TABLE OF CONTENTS1. INTRODUCTION .................................................. 1 2. THE SMTP MODEL ................................................ 2 3. THE SMTP PROCEDURE ............................................

https://datatracker.ietf.org/doc/html/rfc821

rfc5321

Network Working Group J. Klensin Request for Comments: 5321 October 2008 Obsoletes:2821 Updates:1123 Category: Standards Track Simple Mail Transfer Protocol Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements.

https://datatracker.ietf.org/doc/html/rfc5321

rfc822

RFC # 822 Obsoletes: RFC #733 (NIC #41952) STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES August 13, 1982 Revised by David H. Crocker Dept. of Electrical Engineering University of Delaware, Newark, DE 19711 Network: DCrocker @ UDel-Relay Standard for ARPA Internet Text Messages TABLE OF CONTENTS PREFACE ....................................................ii 1.

https://datatracker.ietf.org/doc/html/rfc822

协议详情

端口：25

EHLO

HELO

MAIL

RCPT

DATA

RSET

NOOP

QUIT

VRFY

常用顺序

telnet smtp.163.com 25    //登陆 smtp.163.com 端口号为 25
Trying 202.108.44.205...
Connected to smtp.163.com (202.108.44.205).
Escape character is '^]'.
220 163.com Coremail SMTP(Anti Spam) System
HELO localhost  // 与服务器打招呼，并告知客户端使用的机器名字，可以随便填写
250 OK 
AUTH LOGIN     //使用身份认证登陆指令
334 dXNlcm5hbWU6
cmVkc29zMw==  //输入已经base64_encode()过的用户名.
334 UGFzc3dvcmQ6
MbM2MDQ3NQ==  //输入已经base64_encode()过的密码
235 Authentication successful
MAIL FROM:<redsos3@163.com>  //告诉服务器发信人的地址
250 Mail OK
RCPT TO:<yourframe@21cn.com> //告诉服务器收信人的地址
250 Mail OK
DATA   //正面开始传输信件的内容，且最后要以只含有 . 的特殊行结束。
354 End data with <CR><LF>.<CR><LF>