Telnet to send mail

A blast from the past!

Yes, you can use telnet to send an email using the Simple Mail Transfer Protocol (SMTP). Here's a step-by-step guide:

Prerequisites:

  1. You have a working telnet client on your system.
  2. You know the SMTP server's hostname or IP address and the port number (usually 25 or 587).
  3. You have a valid email address and password.

Sending an email using telnet:

  1. Open a telnet client and connect to the SMTP server:

    telnet <smtp_server> 25

    Replace <smtp_server> with the hostname or IP address of your SMTP server.

  2. Once connected, you'll see a response from the server, usually something like:

    220 <smtp_server> ESMTP

    This indicates that the server is ready to accept commands.

  3. Start by sending the HELO command to introduce yourself:

    HELO <your_email_address>

    Replace <your_email_address> with your actual email address.

  4. The server will respond with a greeting, usually something like:

    250 <smtp_server> Hello <your_email_address>, pleased to meet you

  5. Now, set the mail from address using the MAIL FROM command:

    MAIL FROM:<your_email_address>

  6. Set the recipient's email address using the RCPT TO command:

    RCPT TO:<recipient_email_address>

    Replace <recipient_email_address> with the email address of the person you want to send the email to.

  7. Create the email message using the DATA command:

    DATA

    This will put you in a mode where you can type the email message. When you're done, type a period (.) on a line by itself to indicate the end of the message.

  8. Send the email using the QUIT command:

    QUIT

    The server will respond with a success message, and the email will be sent.

Example:

Here's an example of sending an email using telnet:

telnet smtp.example.com 25
220 smtp.example.com ESMTP
HELO [email protected]
250 smtp.example.com Hello [email protected], pleased to meet you
MAIL FROM:<[email protected]>
250 2.1.0 <[email protected]>... Sender ok
RCPT TO:<[email protected]>
250 2.1.5 <[email protected]>... Recipient ok
DATA
Subject: Test email from telnet

This is a test email sent using telnet.
.

QUIT
221 2.0.0 smtp.example.com closing connection

Keep in mind that this is a very basic example, and you may need to add additional headers, such as From and To, depending on your email client's requirements. Additionally, some SMTP servers may require authentication or have specific requirements for sending emails.