Resources | How to Manually Send an Email Message Via Telnet to Port 25

Email is sent with SMTP which has been assigned the well-known port 25. Knowing this, we can use Telnet to directly connect to, and place mail directly on, any mail server in the world. The only tools required are a telnet prompt (which is available on any OS that has TCP/IP installed) and a recipient’s email address. No email program, text editor, or browser required.

Instructions
To manually test your mail server you can perform the following!

1. Open a command prompt (start>run>cmd in windows 2000 or greater)

2. Type "telnet [your mail server IP] 25" don't forget the port number 
   - - - this will open an SMTP connection

   
   

3. Type "helo yourdomain.com" 
   - - - server will respond "220 mx.mydom.com SMTP"

   
   

4. Type "mail from:<youremailaddress@yourdomain.com>" 
   - - - server responds "250 Address Ok"

   
   

5. Type "rcpt to:<recipient@recieveingdomain.com>" 
   - - - server responds "550 not local host someotherdomain.com, not a gateway"

   
   
6. Type “data”
7. Type “subject:Some email subject”
8. Type “Text for the email body”