How to test an SMTP server with Telnet.

1. Open a command window.
Start --> Run --> cmd

2. Telnet into the SMTP server on port 25.
telnet (servername) 25

3. Test the SMTP connection by manually sending an email by entering the following command sequence.

helo (your domain name)(enter)
response = 250 OK

mail from:(your Email Address)(enter)
response = 250 OK - mail from "your Email address"

rcpt to:(recipient address)(enter)
response = 250 OK - Recipient "recipient address"

data(enter)
response = 354 Send data. End with CRLF.CRLF

To:(recipient's display name)(enter)
From:(your display name)(enter)
Subject:(Subject field of Email message)(enter)
(Enter you body text)(enter)(enter).(enter)
response should be as follows
250 OK

quit(enter)

If you can successfully complete the previous steps, SMTP communications between your computer and the server are working.