sendmail – ServerOK

To test mail using sendmail, use

sendmail -f sender@example.com recipient@example.com
From: Sender Name <sender@example.com>
Subject:  Test Mail
This is a test message.
.

sendmail -f sender@example.com recipient@example.com

From: Sender Name <sender@example.com>

Subject: Test Mail

This is a test message.

Dot in last time tell sendmail that message body is ended and it can send mail.