Telnet Mail Relay

To test a mail server for connectivity and to test sending messages:

Telnet to your mailserver on port 25. Open CMD prompt type "telnet 25
So when the server responds, assuming it does, if not something else may be broken check that first, type:
helo
Server responds with blah blah Hello

Next type: Mail From: John@mymail.com
Server kicks back "Sender Ok"
Type: Rcpt to: John@goingto.com
server says "250 2.1.5 John@goingto.com"

Type: Data
New message "Start mail input"
Type in your test message, hit enter, hit period enter and you should get your message is queued for delivery.