FYI, many people out there do not even realize that emails are sent via tcp/ip port 25 protocol. They told me in order to test, they need a Outlook or Thunderbird client. Those are technical people. :)
cclow@ohost:~>telnet 192.168.0.252 25Trying 192.168.0.252...Connected to 192.168.0.252.Escape character is '^]'.220 openmail.abcmail.sg -- Server ESMTP (Sun Java(tm) System Messaging Server 7.0-0.04 64bit (built Jun 20 2008))helo abcmail.sg250 openmail.ancmail.sg OK, [192.168.0.121].mail from:userA@abcmail.sg250 2.5.0 Address Ok.rcpt to:userB@gmail.com250 2.1.5 userB@gmail.com OK.data354 Enter mail, end with a single ".".subject: test onlyhelo test test test.250 2.5.0 Ok, envelope id 0KNM007R5Y8RIX20@openmail.abcmail.sgquit221 2.3.0 Bye received. Goodbye.Connection to 192.168.0.252 closed by foreign host.