This is an old method of sending email using Telnet. I've posted it here mostly for a remider to me on exactly how to do this, but thought I would share it with others who may not know of this. This can be useful when testing if a server can successfully send email. For example, I use this to confirm if a SharePoint server can successfully send emails for alerts and notifications.
The items in bold are what you should type.
Start a Telnet session from a command line by entering:
Telnet your.mailserver.com 25
220 a.mail.server.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.2499 ready at Thu, 29 Jun 2006 15:59:02 -0600
250 a.mail.server.com Hello [192.168.125.237]
mail from: email@example.com
250 2.1.0 firstname.lastname@example.org...Sender OK
rcpt to: email@example.com
250 2.1.5 firstname.lastname@example.org
354 Start mail input; end with .
This is a test.
. (enter a dot/period to end the data)
250 2.6.0 Queued mail for delivery
Connection to host lost.