Open your telnet client and connect to your Exchange server on port 25
Microsoft Telnet> open exchange.mydomain.local 25
And you’ll see a response like this;
220 exchange.mydomain.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Thu, 20 Aug 2009 12:03:39 +0100
Type the HELO (or EHLO) command;
250 exchange.mydomain.local Hello [192.168.1.2]
Now to begin your message, enter who the message is from;
250 2.1.0 email@example.com....Sender OK
Enter the message recipient;
250 2.1.5 firstname.lastname@example.org
Now for the subject and message part of the message;
354 Start mail input; end with .
subject:This is a test
Hello from me to you
This is a line
250 2.6.0 <EXCHANGEWtIIZS2TRqf0000000a@exchange.mydomain.local%gt; Queued mail for delivery
The last line displayed confirms that your message has been received by the SMTP server and is queued for delivery.
See this post for more information on Exchange HELO/EHLO commands.