The telnet application is a handy means of testing SMTP relay server connectivity and your user authentication.
To get started –
1. Ensure telnet is installed/enabled on your PC (assuming you’re using Windows).
2. Get the Base64 encoded values of your username and password (base64encode.org)
3. Have a TO and FROM address ready to go
You can use the following ports: 25, 587, 2525, and for secure sending, 465. From a command prompt (using port 2525 as an example), enter the command below, and a new page will appear where you will enter your encoded login, password, FROM address, TO address, a subject line as shown or use your own wording for the subject, enter some text like “hello,” hit the enter key to generate a blank line, and end the message/connection by entering a single period/enter.
telnet express-relay.jangosmtp.net 2525
220 express-relay.jangosmtp.net ESMTP Welcome to the JangoSMTP trackable email relay system. ehlo express-relay.jangosmtp.net 250-express-relay.jangosmtp.net Hello 66-192-xxx-xxx.static.twtelecom.net [66.192.xxx.xxx], Haraka is at your service. 250-PIPELINING 250-8BITMIME 250-SIZE 31457280 250-STARTTLS 250 AUTH PLAIN LOGIN auth login 334 VXNlcm5hbWU6 enter your Base64 encoded username 334 UGFzc3dvcmQ6 enter your Base64 encoded password 235 Authentication successful mail from:enter your valid FROM address 250 sender
OK rcpt to:enter email@example.com here 250 recipient OK data 354 go ahead, make my day subject:testing express-relay hello . 250 Message Queued (4FEFB870-379A-45ED-A76C-B474AB3F6E71.1) quit 221 express-relay.jangosmtp.net closing connection. Have a jolly good day.