1. Run a cmd as an admin

2. Type the following command:

telnet smtp.office365.com 25

Something similar to this will be shown:

220 SN4PR0401CA0021.outlook.office365.com Microsoft ESMTP MAIL Service ready at Tue, 27 Feb 2018 19:13:51 +0000

3. Type the following command and hit enter, please replace contoso.com with your own domain

ehlo <contoso.com>

The next command we need to add is the MAIL FROM command.  This determines the address to which tests are sent from.

4. Type the following command

mail from: <Ofice365 email address account>


You should receive Ok as confirmation


Now that the MAIL FROM command has been sent we can send the RCPT TO command.  This command tells the SMTP mail server to who the message should be sent.  

5. Type the following command

rcpt to: <Ofice365 email address account>

You should receive Ok as confirmation

The last command to run before starting the body of the message is the DATA command.  This command lets the SMTP mail server know that everything else about to be sent is the body of the message.

6. Type DATA

Now that the DATA command has been sent we can start sending the message contents. 

Hello World,
This is a test message sent from a manual telnet session.

After you add the body, hit enter and type (.) period, on a line itself to complete the session.

7. Lastly the QUIT command is sent to close the connection.

The recipient previuosly added should recieve the test email.