SMTP protocol to send the whole process of mail

 

Use SMTP mail _ to send mail using SMTP to send mail _ _ _ push mail User Guide - Ali cloud https://help.aliyun.com/knowledge_detail/51622.html

Sending mail through the SMTP protocol overall process is as follows:

1. The client uses the telnet command to connect to the SMTP server, a session is established.
2. The client sends a HELO or EHLO command.
3. The client sends a command AUTH authentication for user login (using smtpd way).
4. The client sends a MAIL command specifies the sender.
5. The client sends a RCPT command specifies the recipient.
6. The client sends a DATA command ready to enter the body of the message.
7. Client sends a Command (Command dot) indicates the end of the DATA command.
8. The client sends a QUIT command to end the session.

Examples

To help you get familiar with the process to send mail using SMTP protocol, the following command telnet session example, to describe the SMTP command session.

Note : where S represents the server, C behalf of the client. You can use the Linux command echo -n Content | base64 base64-encoded.

1. $telnet smtpdm.aliyun.com 25
2. S:220 smtp.aliyun-inc.com MX AliMailServer(127.0.0.1)
3. C:EHLO test.com
4. S:250-smtp.aliyun-inc.com
5. S:250-8BITMIME
6. S:250-AUTH=PLAIN LOGIN XALIOAUTH
7. S:250-AUTH PLAIN LOGIN XALIOAUTH
8. S:250-PIPELINING
9. S:250 DSN
10. C:AUTH LOGIN
11. S:334 dXNlcm5hbWU6
12. C:dGVzdEB0ZXN0LmNvbQ==备注：用户名test@test.com的base64编码
13. S:334UGFzc3dvcmQ6
14. C:dGVzdA==备注：用户密码test的base64编码
15. S:235Authentication successful
16. C:MAIL FROM:<test@test.com>备注：注意用<>将发件人扩起来
17. S:250MailOk
18. C:RCPT TO:<test@test.com>
19. S:250RcptOk
20. C:DATA
21. S:354End data with<CR><LF>.<CR><LF>
22. C:subject: test
23. C:from:<test@test.com>
24. C:to:<test@test.com>
25. C:
26. C:test
27. C:.
28. S:DataOk: queued as freedom ###envid=148316944
29. C:QUIT
30. S:221Bye