Using telnet

Using telnet

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 (
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 2525

220 ESMTP Welcome to the JangoSMTP trackable email relay system.
ehlo Hello [], Haraka is at your service.
250-SIZE 31457280
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 here
250 recipient  OK
354 go ahead, make my day
subject:testing express-relay

250 Message Queued (4FEFB870-379A-45ED-A76C-B474AB3F6E71.1)
221 closing connection. Have a jolly good day.