Command What we are doing
telnet mail.blat.tld 25 telnet to a machine that responds to smtp on port 25
HELO blat.tld issue the HELO command to start.
mail from:[email protected] issue the mail from command
rcpt to:[email protected] issue the rcpt to command (this should be a valid address)
data now the data command will allow you to do the rest..

I typed the
stuff in blue.
"Subject:The text you want on the subject line" on the first line for a subject
other headers and the message body follow
end the mail message with a . on a line by itsel.
B:\>telnet blat.tld 25
220 miniRelay Server v0.9.75 ready
HELO blat.tld
250 Hello blat.tld
mail from:[email protected]
250 [email protected] Address Okay
rcpt to:[email protected]
250 [email protected] Address Okay
data
354 Start mail input; end with <CRLF>.<CRLF>
subject:The text you want on the subject line

This is the message body!
.
250 Ok
quit
221 Signing Off