You will require the address of a mailserver before you can send an email via command/telnet.
1) Click start
2) Click run
3) Type cmd and click ok
4) type: telnet mail.domain.ext 25 and press enter
5) You should see a message similar to the one below:
220 mailserver.domain.ext Microsoft ESMTP Mail service, version
6) Type HELO and press enter
7) You should see a message similar to the one below:
250 mailserver.domain.ext Hello [Ip address]
8.) Type MAIL FROM: mail@domain.ext
9) You should see a message similar to the one below:
250 2.1.0 mail.domain.ext Sender OK
10) Next, type the recipients address. Type: RCPT TO: mail@recipientsdomain.ext and press enter
11) You should see a message similar to the one below:
250 2.1.0 mail.recipientsdomain.exe Recipient OK
12) Before you start typing a message, type the word DATA and press enter
13) If you wish to add a subject line, then type: Subject:-type the subject line here-
14) Once you have typed your message, press enter so you start on a blank line, then type a fullstop . and press enter for your message to be queued for processing.
You should see a message similar to the one below:
250 2.1.0 Message accepted or queued
15) Type quit to exit