Open Telnet from the command prompt
telnet <Server> 25
or
putty (http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html)
HELO domain.com
MAIL FROM:Admin@domain.com
RCPT TO: User@Domain.Com
DATA
Subject: test message
this is a test
.
QUIT
using AUTH LOGIN requires both the user name and password to be Base64 Encrypted suggest using http://www5.rptea.com/base64/
Note: telnet by default is not enabled in Vista and Windows 2008, To enable telnet you will need to Add this as a feature