How to test email using SMTP server

Telnet to your smtp server like

telnet smtp.mydomain.com 25

Syntax :

telnet {smtp_domain_name} {port_number}

And copy and paste the below

helo your_domain.com
mail from:<test@your_domain.com>
rcpt to:<to_email@your_domain.com>
data
From: test@your_domain.com
Subject: test mail from command line

this is test number 1
sent from linux box
.

Note : Do not forgot the "." at the end which represents the end of the message

I found this on the web, and added this to Stack Overflow as many end up here.