SENDING EMAIL USING TELNET

The first thing to do is to open connection from your computer to your mail server. Type like this:
telnet [your.mail-server.domain] [port]
telnet test.mail.com 25
[Enter]

You should receive a reply like this:
Trying test.mail.com...
Connected to test.mail.com.
Escape character is '^]'.
220 test.mail.com ESMTP MAIL Service ready at [Day], [Date] [Hour] [TimeZone]

Then, declare you're sending the email from. Type like this:
HELO [your.local.domain]
HELO local.domain.com
[Enter]

You should receive a reply like this:
250 test.mail.com Hello [IP local.domain.com]

Now, give your email address. Type like this:
mail from: mail@your.mail-server.domain
mail from: vandaime@test.mail.com
[Enter]

You should receive a reply like this:
250 2.1.0 Sender OK

Now, give the recipients address. Type like this:
rcpt to: mail@domain.external
rcpt to: yondaime@goblog.com
[Enter]

You should receive a reply like this:
250 2.1.5 Recipient OK

And then, to start composing the message. Type like this:
data
[Enter]

You should receive a reply like this:
354 Start mail input; end with .

If you want a subject for your mail. Type like this:
subject: [type your subject here]
subject: Trial Sending Email
[Enter]
[Enter]

You may now proceed to type the body of your message. I type the message like this:
Dear Me,
[Enter]
I write this post just to remembering my self about this step.
[Enter]
Thanks.
[Enter]
Regards,
[Enter]
Vandaime
[Enter]

And it's important !!! To tell the mail server that you have completed the message. Type like this:
.
[Enter]

Yup, just type a single "."

You should receive a reply like this:
250 2.6.0 <[UNID]@your.mail-server.domain> Queued mail for delivery
or
250 2.0.0 <[UNID]@your.mail-server.domain> Message accepted for delivery

Done. Congratulation. And then you can close connection with type like this:
quit