Ever wanted to know the commands to just run a manual SMTP test and see the results? Here they are…

telnet hostname 25
helo asdf.com
mail from:bob@asdf.com
rcpt to:recipient@domain.com
data <Enter>
This is a test message <Enter>
. <Enter>

Remember that you can enable Telnet in Windows Vista and 7 under Programs and Features -> Turn Windows fatures on or off. Just check the “Telnet Client” box and hit OK.