How to send a test email message using Telnet

Occasionally I’ve had to troubleshoot sending email messages to a particular SMTP server by simulating a mail client (or .NET mail code) by using the telnet client. Here’s how I do it on Windows:

1. Open the command prompt
2. type: telnet smtpserver.domain.com 25 <press enter>
3. type: helo server.com <press enter>
4. type: mail from: you@domain.com <press enter>
5. type: rcpt to: someone@domain.com <press enter>
6. type: data <press enter>
7. Write a test message. Typically, I type something like: hello world! <press enter>
8. To send the message, type a single period (.) on a line by itself and of course, press enter