SMTP(Simple Mail Transfer Protocol)资料备忘

[基本资料]

* RFC 2821 - Simple Mail Transfer Protocol

4.1 SMTP Commands

   4.1.1.1  Extended HELLO (EHLO) or HELLO (HELO)
   4.1.1.2 MAIL (MAIL)
   4.1.1.3 RECIPIENT (RCPT)
   4.1.1.4 DATA (DATA)
   4.1.1.5 RESET (RSET)
   4.1.1.6 VERIFY (VRFY)
   4.1.1.7 EXPAND (EXPN)
   4.1.1.8 HELP (HELP)
   4.1.1.9 NOOP (NOOP)
   4.1.1.10 QUIT (QUIT)

4.2.1 Reply Code Severities and Theory

1yz   Positive Preliminary reply
2yz   Positive Completion reply
3yz   Positive Intermediate reply
4yz   Transient Negative Completion reply
5yz   Permanent Negative Completion reply

x0z   Syntax
x1z   Information
x2z   Connections
x3z   Unspecified
x4z   Unspecified
x5z   Mail system

4.2.2 Reply Codes by Function Groups

      500 Syntax error, command unrecognized
         (This may include errors such as command line too long)
      501 Syntax error in parameters or arguments
      502 Command not implemented  (see section 4.2.4)
      503 Bad sequence of commands
      504 Command parameter not implemented

      211 System status, or system help reply
      214 Help message
         (Information on how to use the receiver or the meaning of a
         particular non-standard command; this reply is useful only
         to the human user)
      220 <domain> Service ready
      221 <domain> Service closing transmission channel
      421 <domain> Service not available, closing transmission channel
         (This may be a reply to any command if the service knows it
         must shut down)

      250 Requested mail action okay, completed
      251 User not local; will forward to <forward-path>
         (See section 3.4)
      252 Cannot VRFY user, but will accept message and attempt
          delivery
         (See section 3.5.3)
      450 Requested mail action not taken: mailbox unavailable
         (e.g., mailbox busy)
      550 Requested action not taken: mailbox unavailable
         (e.g., mailbox not found, no access, or command rejected
         for policy reasons)
      451 Requested action aborted: error in processing
      551 User not local; please try <forward-path>
         (See section 3.4)
      452 Requested action not taken: insufficient system storage
      552 Requested mail action aborted: exceeded storage allocation
      553 Requested action not taken: mailbox name not allowed
         (e.g., mailbox syntax incorrect)
      354 Start mail input; end with <CRLF>.<CRLF>
      554 Transaction failed (Or, in the case of a connection-opening
          response, "No SMTP service here")

4.2.3 Reply Codes in Numeric Order

      211 System status, or system help reply
      214 Help message
         (Information on how to use the receiver or the meaning of a
         particular non-standard command; this reply is useful only
         to the human user)
      220 <domain> Service ready
      221 <domain> Service closing transmission channel
      250 Requested mail action okay, completed
      251 User not local; will forward to <forward-path>
         (See section 3.4)
      252 Cannot VRFY user, but will accept message and attempt
         delivery
         (See section 3.5.3)

      354 Start mail input; end with <CRLF>.<CRLF>
      421 <domain> Service not available, closing transmission channel
         (This may be a reply to any command if the service knows it
         must shut down)
      450 Requested mail action not taken: mailbox unavailable
         (e.g., mailbox busy)
      451 Requested action aborted: local error in processing
      452 Requested action not taken: insufficient system storage
      500 Syntax error, command unrecognized
         (This may include errors such as command line too long)
      501 Syntax error in parameters or arguments
      502 Command not implemented (see section 4.2.4)
      503 Bad sequence of commands
      504 Command parameter not implemented
      550 Requested action not taken: mailbox unavailable
         (e.g., mailbox not found, no access, or command rejected
         for policy reasons)
      551 User not local; please try <forward-path>
         (See section 3.4)
      552 Requested mail action aborted: exceeded storage allocation
      553 Requested action not taken: mailbox name not allowed
         (e.g., mailbox syntax incorrect)
      554 Transaction failed  (Or, in the case of a connection-opening
          response, "No SMTP service here")

* 简单邮件传输协议 - 中文维基 / Simple Mail Transfer Protocol - 英文维基
* SMTP 协议资料 - 中国协议分析网

[扩展资料]

* 使用telnet发送简单“英文”email
* 电子邮件头详揭秘

$ telnet smtp.qq.com 25
ehlo test                   // 报名字（随便写）
auth login
ZXhhbXBsZQ==                // example（邮箱用户名）的base64编码
cGFzc3dvcmQ=                // password（邮箱密码）的base64编码
mail from: <[email protected]>
rcpt to: <[email protected]>
data                        // 以下输入邮件内容，要符合MIME规范
from: [email protected]
to: [email protected]
subject: mailtest
mime-version: 1.0
content-type: text/plain
                            // 这里要空一行再写邮件正文
this is a test mail!
.                           // 结束符
quit                        // 断开连接

[关于MIME]

* 多用途互联网邮件扩展 - 中文维基 / Multipurpose Internet Mail Extensions - 英文维基

* RFC
RFC 1847
    Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted
RFC 2045
    MIME Part One: Format of Internet Message Bodies.
RFC 2046
    MIME Part Two: Media Types. N. Freed, Nathaniel Borenstein。November 1996.
RFC 2047
    MIME Part Three: Message Header Extensions for Non-ASCII Text. Keith Moore。November 1996.
RFC 4288
    MIME Part Four: Media Type Specifications and Registration Procedures.
RFC 4289
    MIME Part Four: Registration Procedures. N. Freed, J. Klensin. December 2005.
RFC 2049
    MIME Part Five: Conformance Criteria and Examples. N. Freed, N. Borenstein. November 1996.
RFC 2231
    MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations. N. Freed, K. Moore. November 1997.
RFC 2387
    The MIME Multipart/Related Content-type

* MIME类型 / IANA已注册的MIME媒体类型列表
* 字符集列表

* Debian Wiki上的MIME

* CSDN技术中心 MIME邮件面面观