A simple mail server written in Java
Client sends a HELO command to the server
- C: HELO example.com
- S: 250 Hello example.com, pleased to meet you.
Client sends a MAIL FROM command to the server
- C: MAIL FROM:[email protected]
- S: 250 Ok
Client sends a RCPT TO command to the server
- C: RCPT TO:[email protected]
- S: 250 Ok
Client sends a DATA command to the server
- C: DATA
- S: 354 Enter message, ending with "end of email" on a line by itself
Client sends the email message to the server
- C: Subject: This is the subject of the email
- C:
- C: This is the body of the email
- C: end of email
- S: 250 Ok: queued as 12345
Client sends a QUIT command to the server
- C: QUIT
- S: 221 Bye
-- In the above simulation, the client initiates the interaction by sending a 'HELO' command to the server to introduce itself. The server responds with a greeting and a message indicating that it's pleased to meet the client.
-- Next, the client sends a 'MAIL FROM' command to identify the sender of the email message. The server responds with an acknowledgement that the sender has been identified.
-- The client then sends a 'RCPT TO' command to identify the recipient of the email message. The server again responds with an acknowledgement that the recipient has been identified.
-- The client then sends a 'DATA' command to indicate that it will be sending the actual email message to the server. The server responds with a message indicating that it's ready to receive the email message.
-- The client then sends the email message to the server, including the subject and body of the message. After the client is finished sending the message, it sends a period (".") on a line by itself to indicate the end of the message. The server responds with an acknowledgement that the message has been queued for delivery.
-- Finally, the client sends a 'QUIT' command to indicate that it's finished with the SMTP session. The server responds with a goodbye message and closes the connection.
For more info you can visit : https://postmarkapp.com/guides/everything-you-need-to-know-about-smtp
