SMTP + IMAP via telnet

Your Input	Meaning
HELO Test	You identify yourself to the mail server using HELO. The server will respond with `250 OK` or a similar status message.
MAIL FROM:user@company.tld	You specify the envelope sender address (MAIL FROM). This address can technically be spoofed. For testing, you may use your own email address. The receiving server must acknowledge with a 2xx status code.
RCPT TO:recipient@example.tld	You specify the valid recipient address where the message should be delivered. The mail server uses this information for routing. The server must confirm with a 2xx status code.
DATA	You indicate that the SMTP envelope is complete and that you will now send the message content (headers and body). The server responds with a 2xx or `354 Start mail input` status.
To: Testuser1	Message header: logical recipient shown in the email client.
From: Testuser2	Message header: logical sender shown in the email client (independent from MAIL FROM).
Subject: Testmail	Message header: defines the email subject.
(empty line)	A blank line separates the message headers from the message body.
Test	Message body content.
.	A single dot on a new line terminates the DATA section and signals the end of the message content. The server should acknowledge acceptance with a 2xx status code.
QUIT	Terminates the SMTP session politely.

¶ SMTP