Here are the basic steps to send an email using Telnet:
Open your command-line interface (CLI). Type the command to connect to the SMTP server: telnet smtp.example.com 25 Once connected, you can start typing SMTP commands, such as:
HELO yourdomain.com – Introduce yourself to the server. MAIL FROM: you@yourdomain.com – Specify the sender’s email address. RCPT TO: recipient@example.com – Specify the recipient’s email address. DATA – Indicate that you’re ready to send the email content. Type your email content and end it with a single period (.) on a line by itself. QUIT – Close the connection.